Who to hire for a rainwater tank to install

Short answer

A licensed plumber, as soon as the tank is connected to anything inside the house — toilets, laundry, or a pump feeding fixtures. A standalone garden tank with a tap on it is not plumbing work. The dividing line is whether tank water can ever reach the drinking water system, because that is what backflow prevention exists to stop.

Plan itThere is time to get more than one quote, which is where the money is.

When it is someone else

Calling the wrong trade costs an attendance fee to be told so. These are the cases where this problem belongs to someone other than a Plumber.

What to do before anyone arrives

  1. Check your council's rules on tank size, siting and setbacks before you buy the tank.
  2. Work out what roof area will feed it. A tank fed from one small section of roof will not fill, whatever its capacity.
  3. Decide now what the water is for — garden only, or toilets and laundry too. It changes the plumbing, the pump and the price.
  4. Check for a rebate. Several states and water authorities have had them, usually conditional on the tank being plumbed to internal fixtures and installed by a licensed plumber.

What to ask when you book

  • Is a backflow prevention device required here, and is it in the quote?
  • Does the quote include the base, the pump, the first-flush diverter and the mains switching device?
  • Who handles the council permit if one is needed?

What changes the price

No dollar figures here: this directory holds no price data and an invented range is worse than none. What follows is what makes one of these jobs cost more than the same job next door, which is the part you can actually use when comparing quotes.

  • Garden-only versus plumbed to internal fixtures.
  • The base and the site access for a large tank.
  • Pump, switching device and the electrical work to run them.
  • How far the tank is from the fixtures it feeds.

Is this licensed work?

Connecting a rainwater tank to internal fixtures, or providing any cross-connection with the mains supply, is licensed plumbing work and is subject to backflow prevention requirements. Some councils also require a permit for the tank itself depending on size and siting.

There is no national register. Search the licence number with the regulator for the state the work is happening in.

Licensing thresholds and certificate requirements differ by state and change with amending regulation, so this page describes the mechanism rather than quoting a figure. The regulator’s own page is the current answer.

Common questions

Who should I hire for a rainwater tank to install
A licensed plumber, as soon as the tank is connected to anything inside the house — toilets, laundry, or a pump feeding fixtures. A standalone garden tank with a tap on it is not plumbing work. The dividing line is whether tank water can ever reach the drinking water system, because that is what backflow prevention exists to stop.
Do I need a plumber for a garden rainwater tank?
Not for a tank that collects from a downpipe and has a tap on it for a watering can or a hose. You do as soon as it is connected to anything in the house, or to a pump that feeds the house, because at that point a cross-connection with drinking water becomes possible.

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Who to hire for

General information about who does what, not advice about your specific job. Licensing, consumer law and council rules differ by state and change; the regulator for your state is the current source. More guides to hiring a tradesperson.