New Jersey American Water Co. notified residents of Monmouth County over the weekend to discontinue outdoor water use such as lawn watering and car washing.
It's also asking residents of some Ocean County communities to voluntarily limit outdoor water use.
Water company spokesman Richard Barnes said there's been a significant spike in water use since the weather turned hot again late last week.
The National Weather Service says New Jersey received only 1.2 inches of rain in June. That's 3.6 inches below normal.