Installing a sump pump can be a smart way to protect your basement from groundwater and flooding — a real concern in many parts of New Zealand, particularly in low-lying areas or homes with older foundations. The short answer is: some parts of the job are DIY-friendly, but connecting the pump's discharge to the stormwater or wastewater drainage system is restricted work that must be carried out by a licensed drainlayer. Read on to understand exactly where the line sits.
What Is a Sump Pump and How Does It Work?
A sump pump sits in a pit (the sump) dug at the lowest point of your basement floor. As groundwater or seepage collects in the pit, the pump automatically activates and discharges the water away from your home — typically to a stormwater drain, a soakage field, or a legal discharge point. There are two main types:
- Submersible pumps — sit inside the sump pit, quieter and more compact.
- Pedestal pumps — motor sits above the pit, easier to service but noisier.
What Work Can a Homeowner Do?
As a homeowner, you can generally carry out the following tasks yourself without a building consent or licensed tradesperson (though always confirm with your local council, as requirements can vary):
- Digging the sump pit in an existing concrete floor (breaking out concrete and excavating the hole).
- Placing and bedding the sump liner/basin in the pit.
- Setting the pump into the liner and connecting the discharge hose or pipe up to — but not including — the point where it connects to the drainage system.
- Choosing and purchasing the pump and associated fittings from suppliers like Bunnings or Mitre 10.
- Backfilling and reinstating around the pit once the liner is in place.
What Is Restricted Work — and Why Does It Matter?
Under the Plumbers, Gasfitters, and Drainlayers Act 2006, connecting any drainage pipe to the existing stormwater or wastewater network is restricted drainlaying work. This means it must be performed (or supervised and certified) by a person registered and licensed with the Plumbers, Gasfitters and Drainlayers Board (PGDB).
If you connect the discharge pipe to a drain yourself without a licence, you risk:
- Fines and enforcement action from your local council.
- Insurance issues — your home insurer may decline a claim if unlicensed work contributed to damage.
- Failed building inspections if you ever sell or renovate.
- Health and environmental risks from incorrect connections (e.g., discharging into the wastewater system instead of stormwater).
The MBIE Building Performance website has clear guidance on what constitutes restricted building and drainage work in New Zealand.
Do You Need a Building Consent?
This depends on your council and the scope of work. Minor drainage work is sometimes exempt under Schedule 1 of the Building Act 2004, but cutting into an existing drainage system or making new connections often falls outside those exemptions. Always check with your local council before starting — don't assume it's exempt. Your licensed drainlayer can also advise and, where required, obtain the necessary consent on your behalf.
What About the Electrical Connection?
Sump pumps run on mains electricity, and this introduces another layer of restricted work. In New Zealand, any new electrical connection, circuit, or fixed wiring must be carried out by a registered electrician licensed with the Electrical Workers Registration Board (EWRB).
However, if your basement already has a suitable weatherproof GPO (general power outlet) nearby, you may be able to simply plug the pump in yourself — most submersible sump pumps come with a standard plug. If a new outlet or circuit is needed, call a registered electrician.
Safety note: Water and electricity are a dangerous combination. Never work on electrical connections near a wet or flooded sump, and ensure the pump is unplugged before any maintenance.
Choosing the Right Pump for NZ Conditions
New Zealand's variable climate — from the wet West Coast to Auckland's heavy summer downpours — means sizing your pump correctly is important. Consider:
- Flow rate (litres per minute) — match this to your expected water ingress volume.
- Head height — the vertical distance the pump must lift water to reach the discharge point.
- Float switch type — vertical floats suit narrow pits; tethered floats suit wider ones.
- Backup power — a battery backup or water-powered backup pump is worth considering in storm-prone areas.
For guidance on moisture management and healthy homes standards, BRANZ publishes useful technical resources for NZ conditions.
Discharge Location — Get This Right
Where the water goes matters. Your licensed drainlayer will ensure the discharge complies with your council's rules. Common legal options include:
| Discharge Option | Notes |
|---|---|
| Stormwater drain | Most common; must not be connected to wastewater |
| Soakage pit/field | Suitable where soil conditions allow; may need council approval |
| Legal boundary discharge | Must not cause nuisance to neighbours |
| Wastewater drain | Not permitted for groundwater/stormwater |
If you're a landlord, note that basement moisture control may also be relevant to your obligations under the Healthy Homes Standards.
When to Call a Professional
You should engage a licensed drainlayer for:
- Any connection of the discharge pipe to the stormwater or drainage network.
- Obtaining building consent where required.
- Advising on the correct discharge point and pipe sizing.
- Any work inside the drainage system (cutting into existing pipes, installing non-return valves in drains, etc.).
You should also engage a registered electrician if a new power outlet or circuit is needed for the pump.
Finding a qualified local drainlayer is straightforward — search tradedirectory.co.nz to find licensed professionals in your area.