Horizons Regional Council has served the New Zealand Defence Force (NZDF) with an abatement notice to stop discharging contaminants from firefighting foam.
The NZDF will need to report what measures it has taken to Horizons by July 1.
Horizons strategy and regulation group manager Dr Nic Peet said NZDF must cease the unauthorised discharge of a contaminant, namely stormwater that contains Aqueous Fire Fighting Foam (AFFF), on to or into land in circumstances where it may enter water.
Contamination around the Ohakea area first surfaced in December when the drinking water supply to five properties was found to be contaminated with chemicals used in historic firefighting exercises and since banned in New Zealand.
It sparked several investigations including by Horizons and the NZDF which are ongoing.