Water leaks can be sneaky — by the time you notice visible damage, a leak may have been running for weeks or even months. Catching a leak early can save you significant money on water bills, repairs, and potential structural damage. Here's how to tell if you have a water leak in your home and what to do about it.
Check Your Water Meter First
The quickest way to confirm a leak is to use your water meter. Most NZ homes have a water meter at the boundary of the property, usually near the footpath.
- Turn off all taps and water-using appliances inside and outside the house.
- Note the reading on the meter (including the small dial or digital display).
- Wait at least 30 minutes without using any water.
- Check the meter again — if the reading has changed, water is flowing somewhere it shouldn't be.
If the dial is moving even slightly, you almost certainly have a leak. This test works for both supply pipe leaks and internal plumbing leaks.
Warning Signs of a Hidden Water Leak
Even without a meter test, your home will often give you clues. Look out for:
- Unexplained spike in your water bill — a sudden increase with no change in usage habits is a classic sign.
- Damp or discoloured patches on walls, ceilings, or floors — especially if they appear without an obvious cause like rain.
- Mould or mildew growing in unusual spots, such as behind furniture or inside cupboards.
- Musty or earthy smells in rooms that should be dry.
- Soft or spongy flooring, particularly around bathrooms, kitchens, or laundries.
- Peeling paint or bubbling wallpaper on walls or ceilings.
- Sound of running water when everything is turned off.
- Wet patches in the garden or lawn that stay soggy even in dry weather — this can indicate an underground supply pipe leak.
Check Common Leak Hotspots
Some areas of the home are more prone to leaks than others. Do a visual inspection of these spots regularly:
Toilets
A leaking toilet cistern is one of the most common — and wasteful — household leaks. Put a few drops of food colouring into the cistern and wait 10–15 minutes without flushing. If colour appears in the bowl, the flapper valve is leaking and needs replacing.
Under Sinks and Vanities
Open the cabinet doors under kitchen and bathroom sinks and check for moisture, staining, or corrosion on the pipes and fittings.
Hot Water Cylinder
Check around the base of your hot water cylinder for pooling water or mineral deposits (white or rust-coloured staining). A dripping temperature and pressure relief (TPR) valve is also worth investigating — some dripping is normal during heating, but constant dripping is not.
Shower and Bath Areas
Leaks behind tiles are common in older NZ homes. Look for grout that is cracking or missing, tiles that sound hollow when tapped, or damp patches on the wall or ceiling of the room below. BRANZ has useful guidance on wet area construction and waterproofing standards.
Outdoor Taps and Irrigation
Check garden taps and any irrigation systems for drips or wet soil around fittings.
Isolate Where the Leak Is Coming From
If your meter test confirms a leak, you can narrow down whether it's inside or outside the house:
- Locate your toby (main shutoff valve) — usually near the meter or at the house wall.
- Turn the toby off and repeat the meter test.
- If the meter stops moving, the leak is inside the house on your internal plumbing.
- If the meter keeps moving, the leak is in the supply pipe between the meter and the toby — this is often underground.
| Meter moving with toby OFF | Leak is inside the house |
|---|---|
| Meter moving with toby ON | Could be inside or outside |
| Meter stops with toby OFF | Leak is in the supply line to the house |
What You Can Fix Yourself
Some minor plumbing maintenance is perfectly fine for a capable homeowner:
- Replacing a tap washer or O-ring on a dripping tap.
- Replacing a toilet flapper valve.
- Tightening loose compression fittings under a sink (hand-tight plus a quarter turn).
- Replacing a showerhead or flexible hose.
Always turn off the water supply before attempting any repairs, and know where your toby is before you start.
When to Call a Professional
Under the Plumbers, Gasfitters and Drainlayers Board (PGDB) regulations, certain plumbing work is restricted and must be carried out by a licensed or certifying plumber. This includes:
- Any work on sanitary plumbing (drains, waste pipes, soil pipes).
- Connecting or modifying supply pipes.
- Work on hot water cylinders and their valves.
- Fixing underground pipe leaks.
- Any work that requires a building consent under the NZ Building Code.
Attempting restricted plumbing work yourself is illegal and can void your home insurance. If you're unsure, it's always safer to call a licensed plumber. You can find qualified local plumbers on tradedirectory.co.nz.
Safety note: If you suspect a leak near any electrical fittings, switchboards, or wiring, do not touch the area — turn off the power at the mains and call both a licensed electrician and a plumber immediately.
For rental properties, landlords also have obligations under the Healthy Homes Standards to maintain properties in a good state of repair, which includes addressing leaks promptly.