Plainview Water Hardness & Quality Report (2026)

Plainview, New York, in Nassau County — a major central Long Island suburban community (Plainview is a significant Nassau County hamlet — a central Long Island community in Oyster Bay Town adjacent to Old Bethpage and Bethpage; Plainview is a classic mid-20th century Long Island post-WWII suburb — developed primarily in the 1950s and 1960s as part of the great Long Island suburban expansion; Plainview is one of the most strongly Jewish-American communities on Long Island (the Plainview-Old Bethpage area has one of the highest concentrations of Jewish-American residents in Nassau County; the community has numerous synagogues, Jewish day schools, and Jewish community institutions reflecting its historically strong Conservative and Modern Orthodox Jewish-American community character)); Plainview is in the heart of Nassau County's central Island technology and business corridor — the Bethpage–Plainview–Syosset corridor along the Long Island Expressway has significant defense and technology employment (the former Grumman (now Northrop Grumman) facility at Bethpage — where the Apollo Lunar Module was built — is in the immediate area; the Nassau-Suffolk technology industry corridor is one of the most historically significant aerospace and defense manufacturing regions in the US), a diverse Nassau County community — draws its municipal water supply via the Nassau County Water Authority. Water hardness in Plainview measures 65.5 mg/L — classified as moderately soft.

Plainview's moderate softness reflects the central Nassau County Long Island Magothy aquifer's calcareous-poor character. The Upper Glacial and Magothy Aquifers at Plainview draw from Cretaceous calcareous-poor Magothy Sand with effective treatment, producing the moderately soft 65.5 mg/L.

With hardness at 65.5 mg/L, Plainview residents enjoy moderately soft water. Nassau County Water Authority consistently delivers water meeting all New York State DEC and EPA Safe Drinking Water Act requirements.