Building consents for dams

Do I need a building consent for my dam?

Under the Building Act 2004 all “large” dams require a building consent from a regional council.

Under the Building Act, a large dam is defined as follows:

"a dam that has a height of 4 or more metres and holds 20,000 or more cubic metres volume of water or other fluid."

The height of a dam is the vertical distance from the crest of the dam, and must be measured-

"(a) in the case of a dam across a stream - to the natural bed of the stream at the lowest downstream outside limit of the dam; and

(b) in the case of a dam that is not across a stream - to the lowest elevation at the outside limit of the dam; and

(c) in the case of a canal - to the invert of the canal".

The crest of a dam is defined to mean the uppermost surface of the dam, not taking into account any camber allowed for settlement, or any curbs, parapets, guard rails, or other structures that are not part of the water-retaining structure; and for the avoidance of doubt, any freeboard is to be considered as part of the water-retaining structure.

Applying for a dam building consent

All North Island regional councils, except Auckland Council, have transferred its powers to process all building consent applications for dams to the Waikato Regional Council. The Waikato Regional Council will also undertake the inspections required during the construction phase and issue the final code of compliance certificate once the dam has been completed.

Information about the requirements for building and maintaining dams and the relevant application forms are available to download directly from the Waikato Regional Council website.

Dams Register

Northland Regional Council and other regional councils are required under the Building Act to maintain a register of large dams for their respective regions.

The register enables councils to contact large dam owners on matters of importance to them, such as new regulations and guidance material on dam safety. If you own a dam, then you should check with us whether your dam should be on the register.

To register your dam, or for general enquiries regarding dams, please contact the council's Consents team.