Moa Flat RWS & Heriot - Aluminium Advisory

An advisory has been issued for customers on the Moa Flat rural water scheme, including Heriot residents, after drinking water samples returned results with aluminium levels exceeding the drinking water standard of 1mg/L.

Routine testing has detected two exceedances, with readings of 1.70mg/L on 3 June 2026 and 1.55mg/L on 12 June 2026, taken from samples at the Edievale sample point.

No health effects would be expected at this level of aluminium exposure, even if water was consumed over a period of weeks to months. This includes effects for people with kidney disease, infants, and children.

Our water supplies are regularly sampled and tested by an accredited laboratory so we can act when there are any issues. It usually takes 10-14 working days for samples to be tested and results provided.

Water regulator Taumata Arowai has been informed.

To address this issue, more testing of this water supply will be undertaken. Flushing of water pipes and cleaning of reservoirs will be investigated.

You can read more about the water advisory by visiting Council's frequently asked questions page.