IAWAI, the council and you
IAWAI took full responsibility for operations on 1 July 2026, and the councils' water and wastewater assets moved across to it. Customer services are shifting over time, so for now you contact the council as usual. IAWAI's own number is 0800 WATERS (0800 928 377).
Neither IAWAI nor the council has published a rule we could find on exactly where the public pipe ends and yours begins, either for water or for the sewer lateral. So before anyone digs near the boundary, ask IAWAI or the council where its pipe stops. Hamilton also doesn't yet have city-wide residential water meters, which means a slow leak on your side won't show up on a meter reading.
Who to ring in Hamilton
| What you see | Who to call | |
|---|---|---|
| Water leak | Water escaping on public land, such as the berm, footpath or road | The council, 07 838 6699 straight away if it's gushing. For a leak on your property, the council says to call a plumber. |
| Sewage | Wastewater backing up inside the home or on your section | IAWAI says this may be your private drain: a licensed plumber or drainlayer. |
| Overflow | Wastewater coming out of a manhole, drain or public pipe | The council, as soon as possible. Gushing from a manhole: 07 838 6699. |
Hamilton facts that change a plumbing job
Old pipes and tree roots
The council says most of its water pipes are fairly new but some are around 100 years old, and that tree roots, soil movement, nearby building and age all cause leaks. Roots get into wastewater and stormwater pipes through joints, especially older ones.
Close to half rent or don't own
At the 2023 Census, 46.4% of Hamilton households didn't own their home or hold it in a family trust, against 34% nationally. If you rent, report leaks and blocked drains to your landlord quickly, in writing.
Gas heating is common
Fixed gas heaters were a main heating type in 16.2% of Hamilton dwellings in 2023, well above the national 9.5%. Firstgas runs the natural gas network here. See Hamilton gasfitting.
Overland flow paths are mapped
The council's Floodviewer shows land likely to flood in a one-in-100-year rain event and the paths water takes when pipes are blocked or full. Plan Change 14, notified in January 2025, updated the flooding rules for new building.
How to check a Hamilton tradie on the PGDB register
Licences for plumbing, gasfitting and drainlaying come from the Plumbers, Gasfitters and Drainlayers Board (PGDB), and each trade is separate. Search the register by the person's first and last name; it doesn't recognise business names. Look for the tick or green mark that shows a current licence, because people whose licence has lapsed still appear.
The entry also shows who they supervise or are supervised by, any licence conditions, and Board disciplinary decisions from the last 3 years. If they're not certifying, check the supervisor's entry as well. Our licence check guide walks you through the register.
Plumbing help around Hamilton
In the city: Hillcrest. Close by in Waikato District, which IAWAI also serves: Huntly. Cambridge and Te Awamutu in Waipā, and Matamata and Morrinsville in Matamata-Piako, are Waikato Waters areas, with their own pages: Cambridge, Te Awamutu, Matamata and Morrinsville.
By job: gasfitting in Hamilton, plus our guides to hot water cylinders, blocked drains, drainlayers and emergency plumbers.
What we would do
Work out first whether the problem is on public land or yours. Water on the berm or road, or sewage from a manhole, goes to the council on 07 838 6699; a leak inside your boundary or sewage backing up on your section is a job for a plumber or drainlayer. With no published rule on where the public pipe ends, ask IAWAI before any digging near the boundary, and check the name of whoever turns up on the PGDB register.