Guilford Water Hardness & Quality Report (2026)
Water Hardness
2.2 grains per gallon
Source
reservoir
pH Level
7.3
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
67.6 mg/L
Est. Daily Cost
$0.10
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Guilford, your appliances are currently losing 5% efficiency due to mineral buildup.
| Appliance | In Guilford | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.4 yrs | 8.5 yrs | -1% |
| Washing Machine | 12.2 yrs | 12 yrs | — |
| Water Heater | 14.1 yrs | 15 yrs | -6% |
Regional Water Comparison
How Guilford compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Guilford, Connecticut | 37.5 mg/L | 6.5 ppt | 🟢 Soft | reservoir |
| Madison, Connecticut | 38.5 mg/L | 6.6 ppt | 🟢 Soft | reservoir |
| North Branford, Connecticut | 91.5 mg/L | 11.2 ppt | 🟡 Moderately Hard | reservoir |
| Branford, Connecticut | 77.5 mg/L | 10 ppt | 🟡 Moderately Hard | reservoir |
| East Haven, Connecticut | 55 mg/L | 8 ppt | 🟢 Soft | reservoir |
National Benchmark
How Guilford compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Guilford | 37.5 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Guilford's Water Unique?
Local geology and source profile
Guilford, Connecticut, in New Haven County on the Long Island Sound shoreline — a historic Connecticut shoreline town with an exceptional preserved town green and the Henry Whitfield State Museum (oldest stone house in New England, 1639) — receives its municipal water from the South Central Connecticut Regional Water Authority (SCCRWA), which draws from reservoir impoundments on the East River and West River watersheds draining Guilford's coastal Connecticut hinterland. SCCRWA serves the greater New Haven area through an interconnected reservoir and distribution system.
The very soft 37.5 mg/L hardness and low TDS of 67.6 mg/L reflect coastal Connecticut's classic Avalonian basement geology. The Guilford watershed and the broader SCCRWA reservoir system drain the Connecticut shoreline landscape underlain by the Avalonian terrane — Precambrian Proterozoic volcanic rocks (including the Milford-Dedham magmatic arc terranes and related metasedimentary rocks) and the Triassic Hartford Basin in some portions — all crystalline or non-carbonate terrains with minimal soluble mineral content. Abundant Connecticut rainfall and protected forested reservoir watersheds maintain extremely soft, low-TDS source water throughout the SCCRWA system.
At 37.5 mg/L, Guilford's water is very soft — excellent for household appliances and comfortable for this shoreline community. Scale forms slowly over many months in kettles and appliances, soap lathers abundantly, and the dishwasher produces spotless results. Annual descaling of heating appliances is adequate. For very soft Connecticut water, residents in older colonial and early-American homes with aging plumbing should briefly flush cold taps before drinking. The PFAS level of 6.5 ppt warrants a certified drinking water filter — the South Central Connecticut corridor's industrial waterway heritage (New Haven's industrial history) and regional military installations (New Haven and the Groton submarine base watershed) contribute to Connecticut's regional PFAS background in the SCCRWA supply.
Geology & Source: Guilford in New Haven County draws from the South Central Connecticut Regional Water Authority (SCCRWA) reservoir system on the East River and West River watersheds — the coastal Connecticut watersheds drain the Avalonian basement terrain (Precambrian schists and metavolcanics of the ancient Iapetan margin) with negligible carbonate content — Avalonian crystalline drainage produces very soft water at 37.5 mg/L in this Long Island Sound coastal community.