Roof water · Sydney Water and NSW Health
A rainwater tank as the house’s water supply
What a tank needs depends on what its water is used for. Sydney Water’s inspection rule turns on whether the tank feeds a toilet, washing machine or hot water system, or is topped up from the drinking water supply; NSW Health’s advice turns on whether you drink it, and it recommends that people in urban areas use the public water supply for drinking and cooking.
A guide published by Dotto about Richmond, New South Wales. General information, not technical or health advice.
By what the water is used for
NSW Health’s upkeep calendar for a tank and the roof that feeds it is on its rainwater tanks page. This page follows the water to where it is used, which is where the rules divide.
| Tank water used for | Inspection | Also |
|---|---|---|
| Garden taps only | Not one of the cases Sydney Water lists as needing an inspection. | An above-ground tank is low hazard for backflow; with a 20 mm or 25 mm meter, no extra device is needed. |
| Toilet or washing machine | The plumber must book and pay for one. | Assess the site and check the backflow requirements, as a property-specific device may be needed. |
| Hot water system | The plumber must book and pay for one. | A heater running between 60 and 70°C kills disease-causing microorganisms; the water should be 50°C or less at the hot tap. |
| Topped up from, or switched to, the mains when empty | The plumber must book and pay for one. | This is the fail-safe that supplies drinking water when the tank runs dry. |
| Drinking and cooking | Follows the connections above. | NSW Health’s advice below applies. |
Ask for the Certificate of Compliance when the work is done. Sydney Water’s page still names NSW Fair Trading for the inspection booking. Plumbing and drainage inspections are now managed by Building Commission NSW, and outside Sydney Water’s sewered areas of the Hawkesbury the council takes inspection bookings instead. Who inspects where sets out the split.
When you drink it
NSW Health says rainwater from a well-maintained catchment that looks clear and has little or no taste or smell is probably safe to drink, and is unlikely to make most people ill. It adds three cautions:
- People with a severely weakened immune system should talk to their doctor about the risks of drinking rainwater. Elderly people and very young children may wish to take extra care by using only boiled or bottled water.
- Rainwater does not contain fluoride. For other sources of fluoride, such as fluoride toothpaste, ask your dentist or dental therapist.
- Bringing rainwater to a rolling boil and letting it cool disinfects it. An electric kettle with an automatic cut-off is suitable. “Be careful when boiling water to avoid the dangers of scalding.”
Lead, pipes and spray drift
NSW Health’s advice on keeping chemicals and metals out of tank water includes:
- Lead on the roof
- Replace lead flashing, or roofing screws with lead washers, with non-lead alternatives such as aluminium flashing or plastic washers, or paint over them where they can’t be replaced.
- Plastic pipe
- Use pipes and fittings of a grade suitable for drinking water. Some PVC pipes, usually those described as “stormwater”, “wastewater” or “rural” grade, may contain lead.
- Treated timber
- Don’t use pesticide-treated timber on a rainwater catchment.
- Crop dusting
- If aerial spraying drifts over the house, disconnect the downpipe from the tank, then clean the roof or wait for the next rain before reconnecting it.
- Solar panels
- Net the gaps between solar panels and the roof so birds can’t nest under them.
When the tank runs low
Carted water should be drinking water from a public supply, delivered in a clean tank by a water carter authorised by the local council. NSW Health says carters must keep a quality assurance program under the Public Health Act 2010 and keep records of deliveries, and that carted water can leave a tank cloudy for a while by stirring up sediment.
Don’t top up a rainwater tank from a river, creek, dam or bore. NSW Health says water from those sources is generally not safe to drink without further treatment and should not be used for topping up. More in bores and groundwater.
Where premises use rainwater for drinking or cooking and serve the public or employees, they must have a quality assurance program and comply with the NSW Public Health Act 2010. NSW Health publishes a template for a small untreated rainwater supply.
For tanks below ground and other second supplies, see backflow and the second water supply. For a tank that floodwater reached, see plumbing after a flood.