Town officials recently announced a further tightening of rules governing outdoor water use. On July 3, the town shifted from Level 3 to Level 4 water restrictions. Under Level 4, outdoor watering with sprinklers or irrigation systems is only allowed on Tuesdays and Saturdays from 7-10 p.m. Watering done with hand-held hoses and watering cans is allowed any time, as is car washing. The restrictions are in place until further notice. The announcement came just over a week after the town had moved to Level 3 restrictions. Both actions were triggered under state regulations when water flow on the Ipswich River dropped below specified levels. The regulations, which apply to all communities that draw water within stressed river basins, were adopted by the state Department of Environmental Protection as a way of protecting those rivers. The two wells and two reservoirs that Danvers uses for its water supply — the system also serves Middleton — are all located in the vicinity of the Ipswich River. The town from May 1 until June 25 had been under Level 2, the seasonal level it typically adopts at that time of year. Prior to May 1, it was under Level 1, in which there are no water restrictions. That level is typically in place from Oct. 1 to May 1.