Where does the water in 73551 come from?

Water for zip code 73551 in Hollister, Oklahoma is provided by 1 water system. Contact your local utility for specific source information, or check our detailed page for your area.

Water Hardness in 73551

Q: Is the water hard in Hollister, OK (73551)?

The average water hardness in 73551 is 5 PPM (0.3 GPG), which is classified as soft. No water treatment is typically needed.

Q: Do I need a water softener in 73551?

At 5 PPM, your water is relatively soft. A water softener is generally not necessary, though some homeowners prefer the feel of softened water.

Hollister, Oklahoma · Tillman County

5 PPM

0.3 GPG

Soft

0Soft60120180300+

Estimated — Nearby Data

Dataset updated March 9, 2026Matched to 1 water systemTap readings can vary by utility zone, treatment, and plumbing. Methodology

Source context

How this ZIP reading is built

This ZIP reading is built from 1 matched water system. When more than one system is matched, the displayed value is weighted toward larger known service populations when that data is available.

Source basis

1 estimated source

This ZIP reading needs local confirmation before equipment sizing or purchase decisions.

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 73551

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.

1 water system

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.

Water System	Source	Hardness	Pop. Served	Data Source
Hollister OK2007102	groundwater	5 PPM Soft	60	Estimated — Nearby Data

Hollister

OK2007102

Soft

5 PPMgroundwater60 servedEstimated — Nearby Data

Nearby Zip Codes

73542894 73553100 73530894 73546894 76364856 7352898 73555100 76373856 73570894 7635450 73540100 73531894

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 Hollister, OK (73551).

Submit Your Data

Frequently Asked Questions

Is the water hard in Hollister, OK (73551)?

Our estimate for 73551 is 5 PPM (0.3 GPG), but it is based on nearby, county, or state-level data rather than a direct treated tap-water report for this exact location. Confirm with your utility or a home test.

Do I need a water softener in 73551?

Do not size a softener from this estimate alone. Confirm the actual tap-water hardness before choosing treatment equipment.

Is hard water in 73551 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 73551?

Zip code 73551 in Hollister, Oklahoma is served by 1 water system.

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.

10 min read

How to Test Water Hardness at Home

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

8 min read