Rainwater Tank Plumbing WA 2026 - Complete Pricing Guide

Rainwater Tank Plumbing Costs in WA for 2026

Rainwater tanks are a genuinely practical water harvesting investment for Perth homeowners, and the plumbing connections that link the tank to useful outlets within the property are what transform a storage vessel in the garden into a functional water supply system. Perth's Mediterranean rainfall pattern, with its long dry summer and concentrated winter rainfall season, creates a specific challenge and opportunity for rainwater harvesting that differs from the situation in cities with more evenly distributed year-round rainfall. A Perth home with a 5,000 to 10,000 litre tank connected to the roof catchment will typically fill the tank once or twice during the July to September peak rainfall period, and the water stored at the end of winter represents a meaningful supplementary supply for summer garden irrigation or for year-round indoor non-potable uses such as toilet flushing and laundry cold supply. Understanding how to size the tank and its plumbing system for Perth's specific rainfall profile, and what the WA regulatory requirements are for connecting the tank to the building's internal plumbing, is the foundation for a cost-effective and compliant installation.

The Water Services Act 2012 (WA) requires that all plumbing connections associated with a rainwater tank installation be performed by a licensed plumber as notifiable plumbing work. This covers the tank's inlet pipe connection from the downpipe, the first flush diverter installation, the overflow connection from the tank to the soakwell or stormwater drainage system, the pump and associated fittings, and any internal plumbing connections from the pump outlet to internal fixtures. The Water Corporation's technical requirements for rainwater tank connections to the internal plumbing system additionally impose specific cross-connection control requirements, requiring a registered backflow prevention device or an approved air gap at any point where the tank supply interfaces with the mains potable water supply. These cross-connection control requirements are enforced to protect the public drinking water supply from contamination by non-potable rainwater, and they are not optional provisions that can be omitted to reduce installation cost.

Perth's water supply context makes rainwater harvesting genuinely worthwhile relative to other Australian cities. Water Corporation's tiered pricing structure means that households consuming above the base tier pay the higher tier rate for all additional consumption, and outdoor irrigation during Perth's dry summer is the dominant driver of above-base-tier water use for most suburban Perth households. A 5,000 litre rainwater tank used exclusively for summer garden irrigation can replace 5,000 to 15,000 litres of mains water per summer season depending on the available storage refill, the garden area irrigated, and the frequency of use. At Water Corporation's upper tier rate, this represents a meaningful annual saving, and for households with larger gardens or multiple irrigation zones, a larger tank with a more comprehensive pump and reticulation connection can produce proportionally larger savings. Our plumbing services guide for WA covers the broader framework of licensed plumbing work in WA that applies to all rainwater tank installations.

The WA Department of Health publishes guidelines for the use of non-potable water sources including rainwater in residential settings, which confirms that rainwater collected from standard residential roof catchments may be used for toilet flushing, laundry cold supply, outdoor irrigation, and other non-potable applications without treatment, provided appropriate first flush diversion is in place and the internal plumbing is correctly identified and separated from the potable supply with compliant backflow protection. Rainwater is not approved for use as a drinking water source in WA without treatment, regardless of the perceived quality of the roof catchment or the tank contents, and any connection to drinking water outlets or to the hot water system must be treated as a high-hazard cross-connection requiring an RPZ valve. Confirming the intended uses of the tank supply at the design stage allows the licensed plumber to specify the correct connection and backflow protection arrangement for each application.

What Rainwater Tank Plumbing Covers in WA

Rainwater tank plumbing in WA covers the full range of connection work from the roof catchment through to the point of use, performed by a licensed plumber as notifiable plumbing work. The scope includes the first flush diverter installed on the downpipe upstream of the tank inlet, which prevents the initial contaminated roof runoff from the first rainfall after a dry period from entering the tank storage. It includes the inlet pipe from the diverter to the tank and the tank's overflow pipe, which must be connected to a compliant stormwater disposal point such as a soakwell or drain. The pump installation on the tank outlet, the pump controller, the outlet pipework from the pump to the point of use, and any filter fitted in the outlet line are all within the licensed plumber's scope. For systems with internal connections, the scope extends to the separate non-potable pipe reticulation from the pump to each nominated fixture, including the Water Corporation compliant trickle-fill or float-valve mains switchover device that maintains supply to those fixtures when the tank runs dry.

Tank supply and installation, as distinct from the plumbing connections, is typically supplied by the tank manufacturer or supplier rather than the licensed plumber. The major tank brands supplying Perth's residential market, including Rhino, Kingspan, Bushmans, and Polymaster, provide the tank itself, the internal strainer fitting, and in some cases the first flush diverter as part of a supply and installation package that does not include the licensed plumbing connections. The licensed plumber connects the plumbing to the already-installed tank rather than installing the tank itself. This distinction matters for quote comparison, as some suppliers offer a combined tank supply and plumbing connection package while others quote tank supply and plumbing separately. Our stormwater drainage plumbing guide for WA covers the soakwell system that typically receives the tank overflow connection, and the interaction between tank overflow management and the property's stormwater drainage performance.

Perth Rainfall Patterns and Tank Sizing

Perth's Mediterranean rainfall regime, concentrated in the May to September winter period with a dry summer from November to April, creates a specific tank sizing challenge that differs from cities with year-round rainfall. A Perth rainwater tank that is correctly sized for the winter rainfall capture, but whose contents are consumed by summer irrigation faster than winter rain can refill it, will run dry partway through summer, at precisely the period of greatest irrigation demand. The sizing question for Perth tanks is not simply how much water the roof can collect in a year, but how to match tank capacity to the combination of winter collection capacity and summer demand drawdown such that the tank provides useful supply through as much of the summer as possible before the mains switchover activates.

For a standard Perth 3 to 4 bedroom home with a 200 square metre roof catchment in a suburb receiving approximately 700 millimetres of annual rainfall, the theoretical roof collection volume is around 140,000 litres per year. However, because most of this rainfall arrives in the winter months, the practical collection sequence is that the tank fills repeatedly during winter and is drawn down progressively through summer. A 5,000 litre tank in this scenario reaches capacity quickly during winter and overflows through the overflow pipe to the soakwell for much of the July to September period; the 5,000 litres stored at the end of winter then provides approximately 50 to 100 days of modest garden irrigation before running dry and triggering the mains switchover. A 10,000 litre tank stores more of the winter capture and extends the summer tank supply period proportionally, but the additional benefit decreases as tank size increases beyond the practical storage that a single winter season can reliably fill. Perth plumbers and tank suppliers experienced in the Perth market will advise on tank size relative to roof area and intended use profile rather than simply recommending the largest available option.

Perth's Hills corridor, covering Kalamunda, Mundaring, Roleystone, and extending into the Shire of Serpentine-Jarrahdale, represents a specific rainwater tank context driven by the Bushfire Prone Land classification that applies to most properties in these areas. Under WA's Planning and Development (Local Planning Schemes) Regulations and the Building Code of Australia's requirements for Bushfire Attack Level (BAL) rated construction, properties in designated Bushfire Prone Land are encouraged to maintain dedicated fire suppression water supplies on-site, and a large capacity rainwater tank with a separate fire suppression outlet can serve this purpose alongside its domestic water harvesting function. The Department of Fire and Emergency Services WA provides guidance on the minimum tank capacity and outlet specification required for property fire suppression in Bushfire Prone Land areas, and homeowners in the Hills corridor planning a rainwater tank installation should consult this guidance and discuss the fire suppression outlet requirement with their licensed plumber at the design stage. Incorporating a fire outlet fitting and sufficient tank capacity for both domestic and fire suppression purposes in a single installation is more economical than adding fire suppression capability as a separate later project.

Kalgoorlie and the Goldfields region present a compelling case for rainwater harvesting for a different reason from Perth metro. With annual rainfall of only 260 to 280 millimetres and with the town water supply dependent on the Goldfields and Agricultural Water Supply pipeline from Perth, any local rainfall capture that reduces pipeline supply demand is genuinely valuable. Kalgoorlie households with larger roof areas and correctly sized tanks can capture most of their annual rainfall in a relatively small number of significant rainfall events, and this captured water provides meaningful supplementary irrigation supply during the long dry season. The practical constraint on Goldfields rainwater tanks is that the low annual rainfall means tanks fill less frequently and total annual capture volumes are lower than Perth metro, so tank sizing expectations should reflect the local rainfall reality rather than Perth metro benchmarks.

Perth's coastal strip suburbs from Cottesloe through Scarborough to Sorrento present a specific tank placement consideration related to groundwater proximity. In areas built on deep coastal sands where the water table may sit at only 1 to 3 metres below the surface, above-ground polyethylene tanks are straightforward to install. An underground or partly submerged tank in these locations requires careful design to manage the buoyancy force of groundwater acting on a near-empty tank, which can push the tank up from its position if groundwater levels are high. Perth plumbers working in coastal suburbs should assess groundwater depth before recommending underground tank installation. Our greywater system installation and maintenance guide for WA covers the complementary water reuse strategy used alongside rainwater harvesting in Perth homes.

A rainwater tank's overflow interaction with the property's soakwell system deserves attention at the design stage. When the tank is full and significant rainfall continues, the overflow volume is substantial, and the soakwell receiving the overflow must be sized for the combined load from tank overflow and any direct roof catchment bypassing the tank. A plumber designing both the tank and the stormwater system for a Perth property should confirm the combined overflow load on each soakwell and adjust sizing accordingly. Our stormwater drainage plumbing guide for WA covers soakwell sizing that should incorporate tank overflow volumes in the total catchment calculation.

First Flush Diverters in WA

A first flush diverter is a device installed on the downpipe upstream of the tank inlet that captures and diverts the first volume of roof runoff away from the tank after a dry period. The first flush of roof runoff carries the highest concentration of accumulated contaminants, including bird and possum droppings, leaf tannins, dust, pollen, and atmospheric depositions that have built up on the roof surface during the dry period. Diverting this initial contaminated flow away from the tank and allowing only the subsequent cleaner runoff to enter the storage significantly improves the quality of the collected water, particularly for systems where the water will be used for internal purposes such as toilet flushing or laundry.

The WA Department of Health's guidelines for rainwater use in residential settings strongly recommend first flush diversion as a precaution for all roof collection systems connected to internal plumbing. The volume of the first flush divert, typically one litre per square metre of roof catchment as a common specification, means that a 200 square metre roof catchment has a first flush volume of approximately 200 litres, which should be diverted before tank inlet flow commences. Standard first flush diverters in the Perth market, including products from Triossi, Rainharvesting Systems, and various proprietary tank manufacturer systems, achieve this by retaining the first flush volume in a chamber that drains slowly via a small orifice between rainfall events, resetting automatically for the next rainfall. The installation cost of $280 to $550 includes the diverter unit, the downpipe modification, and the connection to a garden drip release point. Our blocked drains guide for WA covers the gutter and downpipe maintenance that directly affects the first flush contamination load, and regular gutter cleaning reduces the first flush diverter's workload by limiting the accumulation of organic matter on the roof surface.

Pressure Pumps for WA Rainwater Systems

A pressure pump is required for any rainwater tank application where the tank's gravity head is insufficient to deliver water at the pressure needed for the intended use. For garden irrigation through a standard garden hose or drip reticulation system, gravity supply from a raised tank may be adequate for low-pressure drip systems, but any application requiring reasonable flow and pressure at the outlet, including toilet cistern filling, washing machine supply, and garden hose use, requires a pump. Almost all Perth residential rainwater tanks are installed with a pump, as the flat lot profiles of most Perth metropolitan properties provide little or no useful gravity head from a ground-level tank to the usage points.

Automatic pressure pumps for rainwater systems in Perth are dominated by two well-regarded brands: Grundfos and DAB. Both manufacture compact, automatic pressure pumps designed specifically for residential tank supply applications, with built-in pressure switches that start the pump when a tap is opened and stop it when flow ceases. The Grundfos SB range and the DAB DIVERTRON and AQUAJET ranges are among the most commonly installed residential rainwater pressure pumps in Perth, available through Reece Plumbing, specialist irrigation suppliers, and tank supply businesses. Pump selection should match the system's flow requirements: a pump that is undersized relative to the total flow demand of all connected fixtures operating simultaneously will produce inadequate pressure; a pump that is significantly oversized will cycle on and off rapidly, reducing pump life. A licensed plumber sizing a pump for a Perth residential tank system will calculate the peak flow demand from the nominated fixtures and select a pump with adequate flow and pressure at that demand point, and will set the pump controller's cut-in and cut-out pressure settings appropriately.

Pump placement affects both convenience and longevity. A pump installed inside a ventilated pump box beside the tank, away from direct sun exposure, performs and lasts better than one left exposed to Perth's summer UV and heat. Perth's summer temperatures in the eastern suburbs and outer growth corridors can exceed 40 degrees Celsius on multiple days each summer, and a pump controller exposed to direct afternoon sun in these conditions faces heat stress that can shorten the controller's service life. Most Perth plumbers installing a residential tank pump include a purpose-designed pump enclosure or advise on a sheltered installation position as part of the standard scope. Our hot water system installation guide for WA covers the heat pump hot water systems that are increasingly installed alongside rainwater tank systems in outer Perth suburbs without ATCO gas, creating a combined water management approach that maximises both energy and water efficiency.

Water Corporation Cross-Connection Requirements

Water Corporation's cross-connection control requirements for rainwater tank systems connected to internal plumbing are among the most practically important regulatory dimensions of a Perth rainwater tank installation, and they are the area where unlicensed or poorly informed tank installations most commonly fail to comply. The fundamental risk that Water Corporation is managing is the possibility that rainwater from the tank could flow back into the mains potable water supply network, contaminating the public water supply with non-potable water. This backflow can occur when the mains pressure drops (as during a main break, fire demand, or system maintenance) while the rainwater system is connected to fixtures also served by the mains.

For systems where the tank supplies fixtures that also have a mains connection through a switchover device, the cross-connection control requirement is a registered backflow prevention device at the mains connection point or a compliant air gap between the mains supply and the non-potable tank supply. Water Corporation's accepted arrangement for a trickle-fill mains top-up system, where a small constant flow of mains water is allowed into the tank to maintain a minimum level during extended dry periods, requires an air gap of at least 25 millimetres between the mains inlet and the maximum water surface in the tank. An air gap is a physical separation that prevents any possible backflow; the mains water falls freely into the tank without any connection between the inlet and the stored water, making backflow hydraulically impossible. This air gap arrangement is the most common Water Corporation compliant approach for Perth residential tank top-up systems and avoids the need for a registered testable backflow device with its associated annual testing obligation. Our backflow prevention device installation and testing guide for WA covers the scenarios where a registered backflow device is required rather than an air gap, and the testing obligations that apply to registered devices.

For systems where the tank supplies fixtures through a float-valve or solenoid switchover that selects between tank and mains supply, the switchover device must include backflow protection that meets Water Corporation's technical requirements for the connection type. The standard arrangement uses a dual check valve or a DCVA at the mains connection point upstream of the switchover, registered with Water Corporation for the property's hazard classification. Perth homeowners who have had a tank installed by a non-licensed handyman or by a tank supplier without licensed plumbing involvement should have the installation assessed by a licensed plumber to confirm the cross-connection control arrangement is compliant, as non-compliant installations are both a regulatory risk and a genuine public health concern if they allow backflow into the Water Corporation main. The WA Department of Energy, Mines, Industry Regulation and Safety provides the regulatory oversight framework for plumbing compliance in WA.

Internal Plumbing Connections in WA

Connecting a rainwater tank to internal fixtures, specifically toilet cisterns and washing machine cold supply, is the scope that delivers the greatest water saving per installation cost for Perth households. Toilet flushing represents 20 to 25 percent of total indoor water use in a standard Perth home, and laundry cold supply represents an additional 15 to 20 percent. Supplying both from the tank rather than the mains supply can reduce total household water consumption by 35 to 45 percent for the periods when the tank has water, which in Perth means the entire summer irrigation period if the tank is adequately sized and the mains switchover is functioning. The financial payback on the internal connection plumbing investment, at Water Corporation's tiered pricing, typically runs three to seven years depending on the tank size, the household's water consumption pattern, and the proportion of time the tank has sufficient water to supply the nominated fixtures.

The internal plumbing for a tank-to-toilet and tank-to-laundry connection system must use separate, clearly identified non-potable pipe reticulation from the pump outlet to each fixture. Under the WA Plumbing Code and Water Corporation's technical requirements, non-potable internal pipe must be coloured or banded in lilac/purple, and all fitting, valve, and outlet labels must clearly identify the supply as non-potable rainwater. This identification requirement prevents future occupants, emergency services, or plumbers from inadvertently confusing the non-potable tank supply with the potable mains supply, which could lead to cross-connection or to someone unknowingly consuming non-potable water from a labelled outlet. A Perth plumber installing an internal tank connection system should use purple pipe or purple-banded pipe throughout the non-potable circuit and label all valves and outlets in accordance with the WA Plumbing Code requirements.

The mains switchover device, which activates automatically when the tank level drops below the minimum sensor level, maintains continuous supply to the nominated fixtures from the mains when the tank has insufficient water. The switchover must incorporate the compliant cross-connection control arrangement described above, and the device should be designed to return to tank supply automatically when the tank refills after rainfall. Perth homeowners with installed switchover systems should test the automatic changeover function annually by allowing the tank to approach the low-level switch point and confirming that the mains supply activates smoothly and that the system returns to tank supply after artificial refill. A switchover device that is stuck in mains supply mode means the tank supply benefit is being lost despite the water being available in the tank. Our new home plumbing guide for WA covers the greywater-ready and rainwater-ready rough-in provisions that are best specified during new home construction to minimise the future cost of adding these internal connections.

Rainwater Tank Brands in WA

Perth's residential rainwater tank market is served by both national and WA-specific tank manufacturers and distributors, with the product range covering slimline tanks for narrow side passages through to large round tanks for rural properties. Rhino Tanks, manufactured in Australia and available through Perth tank suppliers, is one of the most widely installed residential tank brands in Perth, offering a range of slimline, round, and underground tank configurations in polyethylene with long warranties and strong trade support. Kingspan Tanks, another Australian-manufactured polyethylene tank brand, is widely available through Perth's plumbing and irrigation supply network and offers a comprehensive range of residential sizes and configurations. Bushmans Tanks produces a range of polyethylene tanks widely installed in Perth residential and rural applications, with a strong presence in the outer growth corridor and regional markets. Polymaster, based in Victoria, produces polyethylene tanks distributed through Perth plumbing and irrigation merchants.

Steel panel tanks from manufacturers including Aquaplate and Pioneer Water Tanks provide a rectangular or square footprint option for properties where the tank needs to fit into a confined space or match a specific garden design. Steel panel tanks are assembled on site in the available space, which gives them more flexibility in dimensions than a moulded polyethylene tank that must be delivered as a finished unit. They are typically more expensive per litre of storage than equivalent polyethylene tanks but offer the fitting flexibility and a longer structural lifespan under Perth's UV conditions, as steel does not UV-degrade in the way that lower-quality polyethylene can. For underground rainwater tank installations, where the tank is buried to preserve garden space, Atlantis and Rainstore modular polypropylene systems are used by Perth plumbers for residential applications where below-ground storage is preferred. The Standards Australia body governs the applicable standards for rainwater tank plumbing connections including AS/NZS 3500 and the WA Plumbing Code requirements that apply to all tank installations in WA.

Rainwater Tank Plumbing Costs Across Perth Metro

Perth metro rainwater tank plumbing pricing is broadly consistent across suburban areas, with the primary cost variables being the connection scope, the pump specification, and the site access conditions rather than the suburb location. The outer growth corridor suburbs in the north and south, where Perth's new home construction volume is highest and where ATCO gas is typically absent, represent the most active rainwater tank installation market in Perth, driven by the combination of energy and water efficiency focus in new construction and the absence of gas as a driver toward heat pump and all-electric home design that emphasises water efficiency as a complementary objective.

Perth's inner suburb retrofit market for rainwater tanks, where established homeowners are adding tank systems to existing homes rather than including them in a new build, represents a different cost profile from outer corridor new build installations. In established Perth gardens in Subiaco, Nedlands, Mount Lawley, and Fremantle, the tank installation must work around mature trees, established garden beds, paving, and in double-brick homes, wall structures that limit where pipes can be concealed. An experienced Perth plumber working in the inner suburb retrofit market will assess the available tank positions, the routing options for the inlet and overflow pipes, and the path for internal connections before providing a fixed-price quote, as these site-specific factors drive more variation in cost for retrofit work than for new build installations where the site is open and accessible.

Rainwater Tank Plumbing Costs in Regional WA

Rainwater tanks are more critical to regional WA households than to Perth metro residents in many areas, because reticulated Water Corporation supply may be unavailable, limited, or expensive in regional centres and rural properties. Many regional WA properties, including hobby farms, rural residential lots, and properties in remote townships outside the Water Corporation network, rely on rainwater collection as their primary or sole water supply, which places a premium on the quality and reliability of the collection and plumbing system compared to a Perth metro tank that supplements mains supply. In these contexts, the tank plumbing investment is essential infrastructure rather than a water-saving add-on.

The Kimberley and Pilbara regions present a paradox for rainwater harvesting: the Kimberley receives intense wet season rainfall that could theoretically fill a very large tank multiple times during the November to April wet season, but the existing infrastructure and the remoteness of many properties means that large-capacity tank systems are not as commonly installed as the rainfall volume would suggest. For Broome properties with good roof catchments, a properly designed large-tank system with quality pump and filtration can provide a year-round supplementary supply that significantly reduces dependence on the town water supply during the long dry season. The Department of Fire and Emergency Services WA provides guidance on property water supply preparedness in regional WA, including the recommended tank capacities for fire suppression purposes in Bushfire Prone Land areas, which in the Perth Hills and South West adds a separate sizing consideration to the standard water harvesting calculation.

What to Look For in a Rainwater Tank Plumbing Quote in WA

A well-prepared rainwater tank plumbing quote should specify the scope of the plumbing work separately from the tank supply, identify the pump brand and model being installed, confirm whether the mains switchover arrangement meets Water Corporation's cross-connection control requirements and how it does so, identify any backflow prevention devices to be registered with Water Corporation and the associated registration requirement, specify the pipe material and colour coding for any internal non-potable connections, and confirm the overflow connection arrangement. A quote that specifies pump installation without naming the pump brand and model, or that does not address the Water Corporation cross-connection compliance arrangement, leaves the homeowner without the information needed to confirm compliance or compare quotes meaningfully.

Homeowners comparing quotes should confirm that each quote covers the same connection scope: pump installation only, garden outlet only, internal toilet and laundry connection, or all of the above. A quote for pump and garden connection is not comparable to a full internal connection system quote. For tank systems where the internal connection is included, the quote should specify whether the non-potable pipe reticulation is to be surface-run or concealed within walls, as concealed pipe routing in an existing home requires wall access that adds cost and reinstatement work compared to surface-mounted pipe that is visible but less disruptive. The Australian Competition and Consumer Commission provides guidance on consumer rights in home services contracting applicable to tank plumbing quotes. Always verify your plumber holds a current WA licence through DMIRS WA before authorising work. Our plumbing services guide for WA covers the full licensing and compliance context for all WA residential plumbing work.

Rainwater Tank System Maintenance in WA

A rainwater tank system in Perth requires periodic maintenance to remain effective and to maintain the water quality in the tank at an acceptable level for the intended use. The most important annual maintenance tasks are cleaning the gutters and downpipes feeding the tank to prevent organic debris from entering the collection system, inspecting the first flush diverter chamber to confirm the orifice is clear and the chamber is draining between rain events, checking the tank interior through the inspection lid for any sediment accumulation or biological growth, inspecting the pump and its inlet filter for any obstruction, and confirming the mains switchover device operates correctly by testing the automatic changeover function.

Perth's dry summer creates a specific tank water quality risk: water that has been sitting in the tank for several months without turnover in late autumn, after a dry end to the previous winter, may have accumulated sediment and biological material in the base of the tank that is mobilised when the first autumn rain adds new water to the system. The first flush diverter handles the roof contamination aspect of this first rain event, but the disturbance of sediment in the base of the tank is a separate consideration. Perth tank owners who use the tank for toilet flushing and laundry supply should check the tank interior annually and arrange a tank clean if visible sediment accumulation is present in the base. A licensed plumber or specialist tank cleaning service can pump out the tank base sediment and sanitise the interior without fully emptying the stored water volume in most cases. Our roof and gutter plumbing guide for WA covers the gutter maintenance that is the most direct preventive measure for reducing tank contamination load. For broader water quality context in residential plumbing maintenance, our leaking tap repairs guide for WA and toilet repairs guide for WA cover the fixture maintenance that ensures the tank's supply connections remain functional and leak-free. Backflow prevention device testing that may apply to the tank's mains switchover connection is covered in our backflow prevention device installation and testing guide for WA. Strata properties considering shared rainwater tank infrastructure should review our strata and body corporate plumbing guide for WA for the body corporate responsibility framework applicable to common property water systems. For new home builds incorporating a rainwater-ready rough-in, the detailed scope is covered in our new home plumbing guide for WA, and the thermostatic mixing valve considerations relevant to hot water system temperature management alongside tank systems are covered in our thermostatic mixing valve installation and servicing guide for WA.