What is stormwater?
Stormwater is rainwater that falls onto land and buildings, runs into gutters and downpipes, soaks into the ground or runs off hard surfaces and into waterways.
Council stormwater services
Council provides reticulated piped storm water drainage systems in urban areas. These systems carry your property’s storm water into local streams and rivers.
Council must have consent from the Horizons Regional Council to discharge stormwater into waterways.
Stormwater connections & disconnections
Manawatu District Council has a stormwater connection/disconnection process that enables us to manage the storm water network.
New Service Connections Brochure (499KB pdf)
Stormwater on my property
Stormwater collects on the roofs of houses and is removed from the roof through spouting and downpipes. The water should then flow to a Council stormwater system (where available), a private stormwater system or a private soak hole within the property.
Every homeowner has the obligation to dispose of their stormwater runoff in a way that avoids the likelihood of damage or nuisance to other properties. If stormwater runoff from your building is causing damage or nuisance to another property, you will be required to fix the situation and may expose yourself to liability for damages
This is provided under Clause E1.3.1 of the NZ Building Code E1, which states that “any event that has a 10% probability of occurring annually and which is collected or concentrated by buildings or site work shall be disposed of in a way that avoids the likelihood of damage or nuisance to other property”.
Additionally, it is illegal to introduce any hazardous substances into any part of the stormwater system, as this water is eventually inhabited by wildlife. These hazardous substances can also impact on people when they are introduced into stormwater systems.
If stormwater is not carried away quickly, flooding can occur, resulting in property damage and sometimes personal danger.
Keeping It Clean
It is important to keep stormwater as clean as possible because it is discharged untreated to Manawatu’s rivers, streams and beaches. Therefore residents and businesses must do their part to keep the stormwater network healthy. This includes simple steps such as washing your car on the grass instead of the driveway so that the soap doesn’t get into the system.
Do I have to accept our neighbour’s runoff?
You are only obliged to accept stormwater runoff from properties which would naturally discharge onto your property. Any improvement made to sites must ensure that the extra stormwater is controlled and does not cause a nuisance or damage to your property.
If your neighbour’s runoff is causing a nuisance (which directly affects you or your property) or damaging your property, it is advisable to take the matter up with your neighbour directly.
Council will only intervene where the runoff problem is the direct consequence of construction that Council has given consent to.
Please be aware that if you do any development on your property it may increase the amount of stormwater flowing onto a neighbour's property. Raising the ground level, increasing the impermeable area or blocking a flow path are all likely to impact on someone. You will either need to stop that activity or prevent the extra stormwater flowing across the boundary.
The best solutions to stormwater problems is to manage the problem as close to the source by reducing run off and decreasing impermeable surface area.
Council recommends you take time to talk to your neighbours about any flooding problems you may be experiencing. In many cases, a resolution can be reached that will satisfy everyone’s needs.
You may need to consult a lawyer so that any agreement you make with your neighbour is legally enforceable and appropriate for future owners if the land should it be sold.
Building your new home
Be flood wise - build with nature not against it.
When constructing new buildings like homes, garages or sheds think about how the stormwater will flow over the ground, remember it will naturally and inevitably collect in dips and channels.
Reduce the amount of ground cover with impermeable surfaces such as concrete or asphalt. Permeable surfaces absorb the water reducing the risk of flood and pollution.
Never obstruct an overland flow path - this will cause flooding.
Ensure that habitable floors (those areas of the house such as kitchens, bedrooms and living rooms) are always the correct height above ground level to ensure that stormwater is not able to encroach into the living areas of your property. This height can be found in the District Plan.