All new premises in the Waikato District are now required to have a rain tank under the new Water Supply Bylaw.
The bylaw, enforced from March 2010, is a move by Waikato District Council to create more sustainable water supplies, and encourage storing rainwater for non-drinking use.
What’s required?
A rain tank is required for all new premises that will:
- be more than 30m2; and
- connect to a Council water supply; and
- have facilities that use water such as a toilet/laundry that the roof water could be used for.
All new connections to a Council water supply will have a water meter. The water will be billed based on the amount used.
What’s optional?
- The rain tank does not have to be plumbed into the house. However, if the rain tank is used, (for example, to flush toilets), a Council water supply connection should be provided as backup for dry weather.
- Collected rainwater can be used for potable supply (eg drinking, showers) but provided Department of Health guidelines for roof supples are followed.
- Rain tanks are optional for modifications to an existing premises, including building consents that involve a new water connection.
How big does my tank need to be?
New urban residential premises must have a rain tank of at least 5,000L. There is also a minimum roof area that must be connected to the tank. The required roof area depends on the number of bedrooms.
For rural properties on tricklefeed, the minimum tank size is 22,000L.
Frequently Asked Questions
What are the benefits of rain tanks and water meters?
Rain tanks are an important tool for reducing average water use. In most homes, toilet flushing and clothes washing is typically over 50 percent of the total water used. By sizing your rain tank correctly and plumbing it into the house, it is possible to supply nearly all of this water from rainwater.
Water meters are also an important water conservation tool. They encourage us to think about how much water we use, particularly during summer when our water use is at its highest but rainfall amounts are at the lowest.
Does my rain tank need a consent?
A rain tank will require a building consent if:
- the tank will supply roof water to the house;
- the Council mains will be plumbed to the tank (eg backup supply);
- the tank exceeds 35,000L;
- the tank exceeds 2,000L and is more than two metres above ground; or
- the tank exceeds 500L and is more than four meters above ground.
Unless the tank exceeds the size limits above, installing a rain tank for garden irrigation does not require a building consent.
These criteria apply to both new premises and retrofitting a tank to an existing property. If a consent is required, it can be included as part of the overall building consent.
What if I have to have a stormwater attenuation tank?
It is possible to combine the rain tank and stormwater attenuation tank, but the volume of the tank needed is the sum of the two. The top part of the tank drains quickly to buffer storm flows and the bottom saves water for recycling.
What about rural properties?
The minimum tank size has increased for properties on tricklefeed to 22,000L.
What about commercial properties?
The bylaw requirements are for all new premises, which includes commercial properties. The minimum tank size of 5,000L applies but a larger rain tank may be required for large projects. All new connections using more than 15m3/day will also require a resource consent from Environment Waikato.
What if a rain tank is not practical?
Council will consider alternative designs on a case-by-case basis. The design will need to achieve a similar level of water saving as a complying rain tank would achieve when recycling to any toilets and laundry. Contact the Water and Facilities Team for further information.
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