You have a rainwater tank on the side of the house, or a bore in the back yard, and the dam levels are dropping. The obvious question is whether any of the water restriction rules still apply to you.
The short answer is that in most of Australia they do not. Water restrictions exist to protect drinking water, and the water in your tank or your bore is not drinking water from the mains. Melbourne's permanent rules put it about as plainly as a government body ever does: "These rules apply only to drinking water. They do not apply to greywater, rainwater, bore water, or recycled water."
That is the good news, and it is worth knowing, because it means that when your neighbours are down to a bucket you are usually not. But there are three things that catch people out, and one of them can cost you a fine even in a year with no restrictions at all.
The rule that never stops applying, whatever your water came from
Water restrictions care where your water came from. Stormwater law does not.
Every state has an environment protection law that makes it an offence to let anything other than rain enter a stormwater drain. EPA Victoria states the principle in one line: "Only rainwater should go down stormwater drains. Anything else poses a risk to the health of our waterways." In South Australia, discharging washdown water and cleaning agents to stormwater sits under the Environment Protection (Water Quality) Policy 2015, and the EPA's own guidance is that a home car wash "should be conducted on a grassed or gravelled area, or over a spill safe mat". Failing to comply there can bring a fine, an environment protection order, or prosecution.
Nothing in any of that turns on whether the water came from a tap, a tank or a bore. Once you have added shampoo, wheel cleaner and brake dust to it, it is contaminated wash water. A driveway that drains to the kerb sends it straight to the creek.
So the practical rule is the same one we set out in our guide to home car washing rules by state. Wash on the grass. Tank water and bore water buy you freedom from the water restrictions. They buy you nothing at all from the stormwater rules.
The trap: a tank that tops up from the mains
This is the one that surprises people, and it is worth checking before you assume you are exempt.
Plenty of rainwater tanks are plumbed with an automatic mains top up, so the tank never runs dry and the toilets and laundry keep working through a long stretch of no rain. The moment that happens, some of what comes out of your tank is drinking water, and several authorities treat the whole tank accordingly.
Central Coast Council in New South Wales is explicit that restrictions apply if "the tank is connected to a home's internal plumbing or topped up by the Council's drinking water supply". Sydney Water words its exemption the same careful way, covering rainwater "as long as the rainwater tank or dam doesn't contain drinking water".
If your tank is standalone, gravity fed or pumped, filled only by what lands on the roof, you are outside the restrictions. If it has a mains top up valve, check your own utility's wording before you get the hose out during a restricted period. A tank that has been topped up from the mains is, as far as most of them are concerned, holding drinking water.
Bore water: exempt from restrictions, but not from rules
Bore water is treated as a separate supply almost everywhere, and it is generally outside the drinking water restrictions. Sydney Water lists bore water among its exemptions with a pointed caveat: "some government restrictions apply". That caveat is doing real work, and it means different things depending on where you live.
Western Australia is the strictest by a wide margin. Garden bore users in Perth and Mandurah are on exactly the same watering roster as people on scheme water, with the same two rostered days set by house number and the same requirement to water only before 9am or after 6pm. The winter Sprinkler Switch Off runs from 1 June to 31 August each year and applies to bores as well. Breaches carry $100 on the spot fines, and inspectors patrol seven days a week.
The important detail for washing a car is that the WA roster is written around reticulation. The rules speak to a "reticulation system using garden bore water", not to a person standing there with a hose in their hand. Hand held watering is treated differently from sprinklers. If you are in Perth or Mandurah and you plan to wash the car with bore water during the winter switch off, ring Water Corporation and get it confirmed for your address rather than taking a blog's word for it, ours included.
Queensland is the most relaxed. The state's position is that "the take of groundwater for stock and domestic purposes is permitted in any part of Queensland". South East Queensland has no water restrictions in place at the time of writing, and Seqwater has said medium level drought restrictions will only be considered once combined SEQ Water Grid dam levels reach 50 per cent.
New South Wales allows domestic bore use but regulates the bore itself. To take water under basic landholder rights you still need a water supply works approval to construct the bore, and only a licensed driller may build it. WaterNSW also notes that groundwater is untreated and should not be treated as safe to drink without testing. None of that stops you washing a car with it. It does mean an unapproved bore is a problem regardless of what you use the water for.
Where each state stands
| State or area | Rainwater tank | Bore water | What to watch |
|---|---|---|---|
| Victoria (statewide permanent rules) | Exempt | Exempt | Rules stated to apply only to drinking water. Greywater, rainwater, bore and recycled water all named as outside them. |
| Sydney, Blue Mountains, Illawarra | Exempt if the tank holds no drinking water | Exempt, subject to other government rules | A mains top up valve is what changes the answer. |
| Central Coast NSW | Restricted if plumbed to the house or topped up from the mains | Excluded from restrictions | Council advises checking bore rules separately. |
| Regional NSW councils | Usually exempt | Usually exempt | Severe stages can ban home vehicle washing outright. Lismore Level 4 lists residential car washing as not permitted. |
| South East Queensland | Exempt | Exempt | No restrictions currently in place. |
| Queensland (rest of state) | Exempt | Permitted for stock and domestic purposes anywhere in Queensland | Individual councils on their own supply set their own restriction stages. |
| Perth and Mandurah | Exempt | Same watering roster as scheme water | Sprinkler Switch Off 1 June to 31 August. Roster is written around reticulation, not hand held hoses. $100 fines. |
| South Australia | Exempt | Exempt | Stormwater is the live risk. Wash on grass or gravel. |
This is a guide, not legal advice, and restriction stages change with dam levels. Our state by state car washing guide carries live status links for 49 utilities and councils, so check yours there before a long weekend detail.
The part nobody warns you about: bore water spots worse
Here is the thing that catches people who switch to a bore to beat the restrictions. You solve the legal problem and inherit a cosmetic one.
Water spots are not really about water. They are about what the water leaves behind. Water Corporation describes the mechanism exactly: hard water "may leave spots on drinking glasses, shower screens or garden plants because the minerals remain after the water has evaporated". Your paint is no different from a shower screen in this respect. The droplet goes, the dissolved minerals stay, and what you are looking at is the mineral load of that particular water printed onto your clear coat.
Groundwater usually carries more of that load than mains water does, because it has spent a long time in contact with rock. Water Corporation notes that country customers, supplied primarily from groundwater, are more likely to experience hard water than the Perth metropolitan scheme, which blends surface water and desalinated water. The Australian Drinking Water Guidelines flag hardness as elevated from 200 mg/L. A lot of Australian bores sit comfortably above that.
So a bore that keeps you legal through a restriction period can also be the reason your black duco looks worse after the wash than it did before. Rainwater tanks are the opposite case and generally very low in dissolved solids, though roof runoff brings its own contribution of dust, leaf litter and whatever the birds left behind.
If you have never measured yours, that is the first thing to do. A TDS meter costs very little and tells you in seconds what you are actually rinsing with. Our tap water readings by city and suburb give you a baseline for the mains supply near you, and anything your bore reads above that is the extra mineral load going onto the panel.
Washing on tank or bore water without the spots
The method that works is the same one that works on mains water, with one extra reason to bother.
Wash on the grass, with a bucket or a trigger nozzle, using whichever supply keeps you inside your local rules. Then change what touches the paint last. The final rinse is the only water that gets to leave a mark, because it is the only water still sitting there when the car dries. Everything before it gets wiped, agitated or displaced.
That is what a Spot Free Rinse tank does. Water goes in from your tank, your bore or the tap, passes through HFR (High Flow Resin), and comes out near 0 ppm, and at 0 ppm when the resin is fresh. Nothing dissolved in it means nothing left behind when it evaporates, so the car dries on its own without a towel and without spots. Wash. Rinse. Pack up.
Two practical notes for bore users specifically. Higher mineral content means the resin works harder and needs replacing sooner, so a bore at 600 ppm will get through resin faster than mains water at 90 ppm. And if your bore carries iron or sediment, put a sediment pre filter in front of the tank, because grit shortens resin life and does the paint no favours on the way through. Our guide to the TDS level you need covers where the threshold sits, and the comparison of DI, RO, softeners and distilled water explains why a softener does not solve this particular problem. For the full bore-side playbook, tank sizing at 300 to 600 ppm included, see our guide to washing your car with bore water.
Every tank is assembled and tested in Brisbane, and ships with a TDS meter so you can see the reading go from whatever your bore is putting out to near zero. See the tanks.
Where these rules come from
The restriction and exemption wording above is taken from Melbourne Water and the Victorian permanent water saving rules, Sydney Water's Water Wise Guidelines, Central Coast Council, Lismore City Council, Seqwater, Business Queensland, WaterNSW, Water Corporation and the Western Australian Government's garden bore guidance. The stormwater material comes from EPA Victoria and the South Australian EPA. Checked August 2026.
Restriction stages move with dam levels and bore rules are set by state water departments rather than your water utility, so treat this as general information rather than legal advice, and confirm anything borderline with your own council or utility before you act on it.
Frequently asked questions
Can I wash my car with rainwater during water restrictions?
In almost all of Australia, yes. Restrictions are written to conserve drinking water and rainwater is not drinking water. The exception is a tank that is plumbed into the house or fitted with an automatic mains top up, because that tank may hold drinking water. Check your own utility's wording if yours tops up from the mains.
Is bore water exempt from water restrictions?
From drinking water restrictions, generally yes. From all rules, no. Western Australia puts garden bores in Perth and Mandurah on the same watering roster as scheme water, including the winter Sprinkler Switch Off from 1 June to 31 August. Other states regulate the construction and approval of the bore rather than the day you use it.
Do I still have to wash on the grass if I am using tank water?
Yes. Stormwater law does not care where the water started. It cares what is in it by the time it reaches the drain, and a car wash puts detergent, road grime and brake dust into it. Grass or gravel lets the ground filter it. A driveway sends it to the creek.
Does bore water leave more water spots than tap water?
Usually. Spots are the dissolved minerals left behind after the water evaporates, and groundwater has generally picked up more of them than treated surface water. Measure your bore with a TDS meter and compare it against the mains reading for your area. The gap is the extra load going onto the paint.
Do I need a licence for a bore in my back yard?
It depends on the state, and the requirement usually attaches to building the bore rather than using it. Queensland permits taking groundwater for stock and domestic purposes anywhere in the state. New South Wales requires a water supply works approval to construct the bore and requires a licensed driller. Check with your state water department before drilling.
Can I run a Spot Free Rinse tank off my rainwater tank or bore?
Yes, as long as you have enough pressure and flow to feed it, which usually means a pump rather than gravity. Bore water with visible sediment or iron should go through a pre filter first. Higher mineral content means more frequent resin changes, so measure your supply before you size the tank.
