Lawn irrigation season is here, and the Roslyn Water District isn’t waiting for homeowners to figure out the rules on their own.
The district covers a substantial chunk of Nassau County, running water service to Roslyn, Roslyn Heights, East Hills, Albertson, Searingtown, sections of Greenvale, sections of Old Westbury, and a handful of properties near Mineola. Before sprinkler systems start running full blast this Spring, district officials are pushing residents to understand what’s required of them, not just what’s suggested.
The stakes aren’t abstract. Water consumption in the district triples once warm weather sets in, driven almost entirely by lawn irrigation. That kind of demand spike hammers the infrastructure and, far more critically, draws down the underground supply that every resident in this region depends on. Long Island has no fallback. The island sits over a sole-source aquifer, which means there’s no alternative source waiting if this one gets compromised. What’s down there is it.
“The amount of water that homeowners use skyrockets during the spring and summer, with lawn irrigation being the biggest reason why,” said Roslyn Water District Commissioner William Costigan. “When water demand increases by such a dramatic extent, we run the risk of over-pumping our wells, which compromises the health of our sole-source aquifer and places a tremendous strain on our infrastructure.”
That’s not a boilerplate warning. Over-pumping a sole-source aquifer doesn’t just reduce water pressure. It can cause long-term damage to the water table that can’t be undone quickly or cheaply.
So what does the district actually require? Start with the Smart Controller Requirement. It’s mandatory. Any homeowner running an automatic irrigation system within the district’s service territory must have a smart controller installed. That’s the homeowner’s job to arrange. Don’t expect the district to schedule an installation crew for you.
Smart controllers aren’t complicated gadgets. They connect to WiFi, pull local weather data, and automatically skip or reduce watering cycles when rainfall has already done the work. The payoff is real: homeowners who make the switch can cut water use by up to 30% during the warmer months. Given that water bills tend to drop enough to recover the cost of the device within a year or two, it’s hard to make a serious argument against them.
But the Smart controller alone doesn’t satisfy all the requirements. Residents also have to comply with Nassau County’s Odd/Even Watering Ordinance. The rule is straightforward: properties with odd street numbers water on odd calendar days, properties with even numbers or no numbers water on even days. And regardless of the day, nobody runs irrigation between 10 a.m. and 4 p.m. That 6-hour midday window is when evaporation rates peak. Running sprinklers during those hours doesn’t water your lawn; it waters the air.
The Roslyn Water District layers its own scheduling requirements on top of the county ordinance. Rather than letting thousands of irrigation systems run simultaneously and overwhelm the distribution network, the district staggers demand across the service area throughout the day. That kind of coordination isn’t universal among water districts, and it reflects a straightforward understanding of how distribution infrastructure actually works under load.
The details of that schedule, and the full breakdown of what’s required based on property address, were covered in a piece published on April 9, 2026, by the Long Island Press. Homeowners who aren’t sure which watering day applies to their address should check there, or contact the district directly.
The Nassau County Department of Health also tracks aquifer health across the region. Its data underscores why districts like Roslyn’s can’t treat irrigation management as optional. The 343 square miles of Nassau County share that same underground supply, and every gallon wasted through poorly timed or unregulated irrigation is a gallon that doesn’t go back easily.
Costigan and the district aren’t asking homeowners to stop watering their lawns. They’re asking residents to water smarter, on the right days, outside that 8-hour restricted window, and with equipment designed to avoid waste. That’s not an unreasonable ask when the only aquifer under Long Island is the only one there is.