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Water Hardness in 11724

Cold Spring Harb, New York · Suffolk County

35 PPM
2.1 GPG
Soft
0Soft60120180300+
High Confidence — USGS Monitoring

Dataset updated March 9, 2026Matched to 10 water systemsTap readings can vary by utility zone, treatment, and plumbing. Methodology

Source context

How this ZIP reading is built

This ZIP reading is built from 10 matched water systems. When more than one system is matched, the displayed value is weighted toward larger known service populations when that data is available.

Source basis
10 USGS-backed sources
10 matched systems total for this ZIP; USGS monitoring is used where treated-water reports are unavailable.
Water source profile
Primarily groundwater
Groundwater commonly picks up calcium and magnesium after contact with rock and soil. This profile is weighted by known population served across matched systems.
Data recency
March 9, 2026
Dataset rebuilt March 9, 2026; individual utility reporting years can vary.

Hardness is a mineral-content reading, not a drinking-water safety rating. Use it for scale, appliance, and softener decisions; check your utility report or test your tap before sizing treatment equipment. See how we calculate local readings.

Water Systems Serving 11724

These are the systems matched to this ZIP code. The displayed ZIP value is weighted toward larger known service populations when population data is available.

10 water systems
PWSID is the public water system identifier. Data Source shows whether the hardness value comes from a treated-water report, USGS monitoring, or a local estimate; source year is shown when available.
Suffolk County Water Authority
NY5110526
Soft
37 PPMgroundwater1,100,000 servedHigh Confidence — USGS Monitoring
South Huntington Water District
NY5103263
Soft
20 PPMgroundwater81,760 servedHigh Confidence — USGS Monitoring
Greenlawn Water District
NY5103271
Soft
37 PPMgroundwater42,000 servedHigh Confidence — USGS Monitoring
Riverhead Water District
NY5103705
Soft
24 PPMgroundwater35,000 servedHigh Confidence — USGS Monitoring
Dix Hills Water District
NY5103276
Soft
44 PPMgroundwater34,522 servedHigh Confidence — USGS Monitoring
Showing the first 5 systems. Expand to review all matched systems.

Nearby Zip Codes

117433511797431179143117714311732431174035117213511765431180343117463511747351170943

What This Means For You

Recommendations are based on the displayed ZIP hardness reading. Confirm your tap reading before sizing or buying treatment equipment.

Your Water Is Soft

Your water hardness is in the soft range. You likely don't need a water softener. Enjoy your naturally soft water!

Know your water hardness?

If you've tested your water or have your utility's CCR report, share your reading to help us improve accuracy for Cold Spring Harb, NY (11724).

Submit Your Data

Frequently Asked Questions

Is the water hard in Cold Spring Harb, NY (11724)?

The average water hardness in 11724 is 35 PPM (2.1 GPG), which is classified as soft.

Do I need a water softener in 11724?

At 35 PPM, your water is relatively soft. A water softener is generally not necessary.

Is hard water in 11724 safe to drink?

Water hardness itself is a mineral-content reading, not a drinking-water safety rating. Calcium and magnesium are naturally occurring minerals, but you should check your utility's Consumer Confidence Report for contaminant and compliance information.

How many water systems serve 11724?

Zip code 11724 in Cold Spring Harb, New York is served by 10 water systems.

Learn More About Your Water

Water Hardness Scale: PPM and GPG Chart

Use the USGS water hardness scale to compare PPM, GPG, and mg/L levels from soft to very hard water.

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How to Test Water Hardness at Home

Compare free lookups, soap tests, test strips, liquid drop kits, and lab tests for measuring water hardness.

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