Hamilton City Council is on water alert level one after an increase in water use in December so far.
The water level restriction means sprinkler use must be limited to between 6am to 8am and 6pm to 8pm daily, while hand-held hosing can be done at any time.
Moving to level one will also affect Waikato District residents in Tauwhare, Matangi and Gordonton, as they're supplied by Hamilton's water network. Residents in Waipa and other Waikato District Council areas have not yet moved to an alert level.
Hamilton City Council's city waters manager Maire Porter said Hamilton is just one of many river users who take water from the Waikato River and there is a limit to the amount that can be taken each year.
"December always sees an increase in water consumption and with reduced rainfall expected over the coming months as the weather really starts to heat up, we need to start being conscious about the amount of water we use," Mrs Porter said.