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Water Hardness in 61350

Ottawa, Illinois · La Salle County

147 PPM
8.6 GPG
Moderately Hard
0Soft60120180300+
High Confidence — USGS Monitoring

Dataset updated March 9, 2026Matched to 7 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 7 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
7 USGS-backed sources
7 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 61350

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.

7 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.
Ottawa
IL0990800
Moderately Hard
147 PPMgroundwater18,097 servedHigh Confidence — USGS Monitoring
Naplate
IL0990600
Moderately Hard
147 PPMgroundwater465 servedHigh Confidence — USGS Monitoring
Fields Hill Improvement Association
IL0995150
Moderately Hard
147 PPMgroundwater312 servedHigh Confidence — USGS Monitoring
Retz Addn Improvement Association
IL0995400
Moderately Hard
147 PPMgroundwater168 servedHigh Confidence — USGS Monitoring
La Salle County Nursing Home
IL0995329
Moderately Hard
147 PPMgroundwater100 servedHigh Confidence — USGS Monitoring
Showing the first 5 systems. Expand to review all matched systems.

Nearby Zip Codes

What This Means For You

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

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 Ottawa, IL (61350).

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Frequently Asked Questions

Is the water hard in Ottawa, IL (61350)?

The average water hardness in 61350 is 147 PPM (8.6 GPG), which is classified as moderately hard.

Do I need a water softener in 61350?

With hardness of 147 PPM, a water softener is worth considering for homes in 61350.

Is hard water in 61350 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 61350?

Zip code 61350 in Ottawa, Illinois is served by 7 water systems.

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