Selectmen have instituted mandatory limits on nonessential water use through September to help meet state water conservation benchmarks. The board will hold a public hearing on the issue during its 7 p.m. meeting Tuesday in Town Hall. Under the temporary restrictions, residents will be allowed to use sprinklers or automatic irrigation systems two days per week, but only before 9 a.m. and after 5 p.m., with violations subject to a $50 fine. Lawns on properties with even street numbers may be watered on Mondays and Thursdays; addresses with odd numbers can be watered on Tuesdays and Fridays; the use of sprinklers or automatic systems will not be allowed on Saturdays, Sundays, or Wednesdays. Watering with a hand-held hose is allowed during the restricted period, according to an announcement detailing the new limits posted on the town’s website, www.needhamma.gov. Selectmen made the decision to help meet the state Department of Environmental Protection’s goal of a per-capita water use of 65 gallons per day. For the past few years, Needham’s rate was nearly 68 gallons per day; limiting the town’s water use may help it avoid stricter restrictions in the future, Selectman Dan Matthews said in a phone interview. The town’s water restriction does not apply to businesses, he said.