A rainwater tank collects water off your roof. Used well, it cuts your mains water use and keeps the garden green during dry spells.

What it can be used for

Common uses are garden watering, toilet flushing and the laundry. Drinking rainwater needs extra care and treatment, and not every roof or tank is suitable.

Tank size and placement

Size depends on roof area, rainfall and how you will use the water. Place the tank on a firm base near a downpipe.

The pump

A pump moves water from the tank to taps and fixtures. Choose one with the right flow and pressure. Pumps need to be fitted and set up correctly so they do not run dry.

Mains top up

A mains switch or top up valve can feed town water into the tank when it runs low, so toilets still flush in a dry spell.

Keep it clean

Clean gutters, fit leaf screens and a first flush diverter, and check the inlet and overflow for blockages. Mosquito mesh is needed on openings.

Rules

Rules vary for installation and connection to household plumbing. Backflow protection is important. A licensed plumber knows what applies.

We can help

We install and service rainwater tanks and pumps and can advise on options.

Choosing the right tank

Tanks come in poly, steel and concrete, and in slimline shapes for tight side passages. Poly tanks are light and common. Steel tanks last well when coated. Choose a size based on how much roof you can collect from and how you plan to use the water. A bigger tank gives you a buffer in a dry spell, but it also needs more space and a stronger base.

Pump types and setup

Pressure pumps run when a tap opens and stop when it closes. Some pumps are built into a control unit that switches between tank and mains. The pump needs a clean water supply, a filter on the inlet, and a spot out of the weather. Noise is worth thinking about if the tank sits near a bedroom.

Plumbing it to the house

Connecting tank water to toilets and the laundry needs separate pipework or a managed switch, plus backflow protection so tank water cannot enter the mains. It is regulated work, so use a licensed plumber and ask for the compliance paperwork.

Care through the year

Check gutters before autumn, clean the leaf screens, look at the first flush device and inspect the tank for sludge every few years. Keep overflow pipes clear so a big storm does not flood the base.

Is it worth it?

Savings depend on rainfall, tank size and what you use it for. A tank can lower mains use for the garden and toilets, and it adds some drought resilience. We will tell you honestly if a tank suits your property.

The questions that decide whether a tank is worth it

A rainwater tank sounds like an easy win, and sometimes it is. Before you buy, work out what you want it for. Watering the garden and washing the car is a simple setup. Flushing toilets and running the laundry means connecting the tank to the house plumbing, and that is a bigger job with more rules. Drinking tank water needs treatment and care, so most households skip it and keep drinking mains water.

Then work out how much roof you can collect from and how much rain you realistically get. A big tank on a small roof stays half empty. A small tank on a big roof overflows. Ask the supplier how they sized it and what assumptions they made. If the answer is only "most people buy this size", keep asking.

Pump trouble is the most common complaint

Most tank owners end up calling a plumber about the pump, not the tank. A pump that runs dry burns out. A pump that switches on and off every few seconds usually has a pressure or air problem. A pump that runs constantly can mean a leak somewhere on the line. If you hear it cycling when no tap is on, shut it off and look for a dripping tap or a leaking fitting before it fails.

Ask whoever installs the pump about dry run protection, where the pump sits so it stays dry, and what to do in a power cut. Check council or water authority requirements before you start, especially for any connection to the house. Mains top up and backflow protection are not optional extras if the tank feeds indoor outlets.

What to do at the start of each season

Check the gutter and first flush device that feed the tank. Look at the screens on the inlet and the overflow for leaves and insects. Check the tank for sediment and algae if it has been a while. Listen to the pump for any change in sound. Test the mains top up to make sure it still works.

Small checks before summer and after autumn leaf fall prevent most tank problems. If you notice a smell, a colour change or a pump that cycles, deal with it early.

Common problems

Pumps that cycle on and off often usually have a small leak or a pressure tank issue. A tank that smells has sludge or a dead animal in it and needs cleaning. Overflow that sprays against a wall needs a pipe directing it to a drain.

What to ask before you install

How much roof can I collect from? What will I use the water for? Where will the tank go? Do I need council approval or a permit? How will the pump be powered and protected? Who will maintain it? Answering these first stops you buying the wrong size or the wrong pump. A plumber can inspect your roof, gutters and the proposed site and give practical advice.

Checking an existing tank before you buy a house

Look at the condition of the tank, gutters and first flush device, check for leaks and for mosquito screens, ask what the water is used for, and ask for any installation records. A tank connected to the house needs correct backflow protection.

A plumber can check the connections and the pump and tell you what needs work.

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