You can change a tap washer. You cannot swap a toilet. The line between homeowner DIY and restricted work is narrower than most people expect — and it moves if the house is a rental.
Plumbing looks like fair game for a confident DIYer, provided nothing leaks afterwards. New Zealand law takes a narrower view. Most plumbing is restricted work, and the list of what a homeowner may legally do is short and specific.
What you can do yourself
The homeowner exemption covers genuinely low-risk maintenance:
- Replacing tap washers and O-rings on existing taps.
- Replacing or repairing taps, ball cocks and plugs.
- Swapping a shower head on an existing arm, where no pipework is altered.
- Installing a washing machine or dishwasher onto existing connections.
The common thread: you are working on something already installed, at a fitting designed to be serviced, without altering pipework.
What you cannot
Anything that installs, alters or repairs a sanitary fixture connected to the water supply, or connects and disconnects fixtures to the water supply, is restricted to licensed tradespeople. In practice that means:
- Replacing a toilet, basin or vanity unit.
- Moving or extending pipework of any kind.
- Hot water cylinder work — installation, replacement, or the valves around it.
- Anything at all involving gas. Gasfitting is fully restricted; there is no homeowner exemption.
Replacing a toilet catches people out constantly, because it looks like unbolting one object and bolting down another. It is still restricted work.
The rental trap
This is the part that costs landlords money: the homeowner exemption only applies to the home you live in. It does not extend to a rental, an investment property, a holiday home you let out, or anything commercial.
So the tap washer you may legally replace in your own bathroom is restricted work in the flat you own down the road. Plenty of small landlords do not know this until something goes wrong and an insurer starts asking who did the work.
Why the rules are strict
Contamination is the first reason. Potable water systems can be back-siphoned or cross-connected by the wrong fitting in the wrong place, and that risk reaches the street supply, not only your house.
Scalding and pressure are the second. Hot water systems run at temperatures and pressures that injure people when the controls are wrong, and the valve arrangement on a modern cylinder is not self-explanatory from looking at it. See what changed in the hot water rules.
Unlicensed restricted plumbing work carries fines of up to $10,000. The more common cost is an insurance claim argued over who did the work, or a sale delayed while a buyer's lawyer asks for paperwork nobody has.
When to stop
Some jobs are legal for you but still depend on details that are easy to miss: falls, clearances, seals, isolation. If you are partway into one and it has stopped looking simple, stopping costs less than continuing. Taking a tap apart three times usually ends with a plumber replacing more than the washer.
Tony holds both PGDB licences, plumbing and gasfitting, and works across Paraparaumu, Waikanae and the wider coast. If you are not sure which side of the line your job sits on, ask or call 021 198 3113 — it is a quick conversation.