Water filter installation in New York City

What the water is like across New York City

The city runs the largest unfiltered surface supply in the United States, and holds a filtration avoidance determination to do it. The Bronx is the exception: the Croton Water Filtration Plant under the Mosholu Golf Course is the one plant the surface supply has, so part of that borough drinks the only filtered New York City water. Manhattan's distinguishing feature is vertical. Main pressure reaches about the sixth floor, so above that the last stage of the supply is a rooftop tank operated by the building owner, inspected annually under Health Code article 141. Staten Island is the only borough whose water crosses open water, through the Richmond Tunnel some 900 feet beneath Upper New York Bay. Queens has a retired groundwater system, out of service since 2007. One rule holds across all five: the property owner owns the entire service line, not merely the private half.

What this means locally

Tenure shapes what you can actually do here more than water chemistry does. A tenant cannot treat a building, cannot touch the riser and cannot reach the rooftop tank, which rules out whole-building filtration for most households in the city before any technical question is asked. What a tenant can do is fit a point-of-use filter at the kitchen tap, and on this supply that is not a compromise: it treats the water you drink at the last possible moment, after the tank, after the riser and after the internal plumbing. Co-ops and condos face a different problem, where a lead service line is a building capital decision rather than an individual one, and the city's ownership rule puts the entire line on the property owner rather than splitting it at the curb. City records identify roughly 121,100 known lead or galvanised service lines across the five boroughs. The Department of Environmental Protection supplies a free lead test kit through 311 and publishes a searchable service line map, and both are worth using before anybody spends money.

Utilities we have researched here

One utility supplies the researched towns in this region.

• New York City Department of Environmental Protection

What that means for equipment

• Reported hardness across the towns measured here runs from 1.8 to 1.8 grains per gallon. That is a narrow spread, so the softening decision is reasonably consistent across the region.
• 3 towns use chloramine rather than free chlorine as the residual disinfectant. Chloramine needs catalytic carbon or a much longer contact time than a standard cartridge gives it, and a softener on it should be specified with chloramine resistant resin.
• 1 draw at least part of the supply from groundwater. Groundwater is steadier through the year than surface water and usually harder, and it tends to bring iron and manganese rather than the seasonal taste changes a reservoir produces.
• 5 have a documented lead service line position. In every one of them the lead comes from the service line or the plumbing inside the building rather than from the supply, so the measurement that answers it is a first draw sample taken after water has stood overnight.
• 2 have a published PFAS position. Where treatment is warranted it is granular activated carbon or reverse osmosis certified to NSF/ANSI 58. Where the utility already treats for it at the plant, a household system adds nothing.

Towns we cover in New York City

Each has its own page carrying the utility, the source water, the treatment and the lead position, with every figure attributed to a publisher and the year it refers to.

The researched towns side by side

Every figure below is taken from the town page it links to, where it carries its publisher and the year it refers to. A blank means we hold no sourced figure for that town rather than that the value is zero.

Systems we install here

Installation and service across New York City

Other regions in New York

Or read the New York hub for the state regulators, the PFAS and lead rules that apply across New York, and every area we cover there.