PORTSMOUTH — Summer watering restrictions imposed by the Portsmouth Water and Fire District — at times voluntary and other times mandatory — will be lifted altogether next Tuesday, the day after Labor Day.

On July 18, the water and fire district asked customers to limit outdoor watering to alternate days on a voluntary basis, but made the measure mandatory three days later, in the midst of a heat wave and dry spell, accompanied by peak water demand.

After three weeks, the conservation program returned to voluntary status as some rain fell, temperatures cooled and demand for water eased, according to Joseph Magliocco, chairman of the administrative board.

In a statement, he said that the conservation efforts were successful in helping reduce water demand “to a manageable level” during extended dry weather.

Earlier in the summer, general manager William J. McGlinn explained that the high demand for water strained the district’s pumping capacity, which tops out at 2.5 million gallons a day.

Water demand has now returned to normal levels, Magliocco said.