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Local water dashboard

Official source aggregation

Water quality in Culbertson, MT 59218

A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Roosevelt County.

1 reported benchmark flag
Primary matched system
Dry Prairie Rural Water Authority
Source water
Surface water
County
Roosevelt County
Profile updated

At a glance

What the current records say

Hardness

Very Hard

321 PPM · 18.8 GPG

Compliance screen

No active flag

0 active health-based records

Lead 90th percentile

0.003 mg/L

20% of action level

Utility match

2 systems

Serves 3,005 people system-wide

Hardness meter

How hard is the water?

Very Hard

Estimated local hardness

USGS hardness classification scale

321 PPM

Soft
0–59Moderate
60–120Hard
121–180Very hard
181+

Parts per million

321

mg/L as CaCO₃ equivalent

Grains per gallon

18.8

1 GPG ≈ 17.1 PPM

What this means at home

At 321 PPM, mineral scale can build up on fixtures and heating elements, reduce soap lather, and leave visible spotting. Hardness is primarily an aesthetic and appliance concern—not itself a tap-water safety rating.

USGS sites used

7

Nearest site

31.6 mi

Observation range

Jan 12, 2016–May 27, 2026

Estimate confidence

Low

Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: Yellowstone River near Sidney MT (Stream).USGS source documentation ↗

Regional context

Is 59218 typical?

These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.

Culbertson median

321 PPM

About the same

1 indexed ZIP readings · Range 321–321 PPM

Montana median

122 PPM

199 PPM higher

129 indexed ZIP readings · Range 0.2–799.5 PPM

EPA benchmark screen

Contaminant snapshot

Available numerical results from associated SDWIS community water systems, compared with the applicable action level or federal MCL. Federal measured-value coverage is incomplete.

1 pass1 fail

Lead (PB90)

0.003 mg/L

Reported Dec 31, 2021

Copper (CU90)

1.35 mg/L

Reported Jun 30, 2016

Numerical coverage

2 comparable results

Missing values remain blank; absence is not treated as a pass.

Lead (90th percentile)

Measured in mg/L

Pass

Local 0.003

EPA limit 0.015

Local level is 20% of the listed EPA limit.

Copper (90th percentile)

Measured in mg/L

Fail

Local 1.35

EPA limit 1.3

Local level is 104% of the listed EPA limit.

Share of EPA benchmark

100% line = listed limit

EPA SDWIS compliance

Reported violation history

Open EPA source documentation ↗
2026Q2
All records
3
Health-based
0
Active health-based
0
Contaminant or ruleSystemStatusPeriod
Lead and Copper RuleMT0004348UnaddressedOct 1, 2024
Total Haloacetic Acids (HAA5)MT0004348ResolvedJan 1, 2024through Dec 31, 2024
TTHMMT0004348ResolvedJan 1, 2024through Dec 31, 2024

No reported violation does not prove that every contaminant was tested or absent; SDWIS measured values are incomplete and lag state records.

Solutions matcher

Your personalized water action plan

Matched to Culbertson ZIP 59218 using 321 PPM nearby hardness and 2 reported measurement benchmarks.

2 matches

Scale protection

High-Capacity Whole House Water Softener

321 PPM is 3× the high-hardness trigger used by this matcher.

Designed to reduce scale on fixtures, water heaters, glassware, and plumbing throughout the home.

Compare whole-house systems

Drinking water protection

Under-Sink Reverse Osmosis System

Copper (90th percentile) has a measured benchmark flag or active health-based SDWIS record in this profile.

A certified multi-stage RO system targets a broader range of dissolved contaminants at the kitchen tap.

Explore under-sink filtration

Affiliate disclosure: we may earn a commission from qualifying purchases, at no added cost to you. Product matching is educational and does not replace certified water testing.

Frequently asked

Water questions for Culbertson

Is tap water safe in Culbertson?+

EPA ECHO shows no active health-based violation for the associated systems in this reporting snapshot. This does not prove every contaminant is absent; federal records can lag and household plumbing can change tap conditions.

How hard is the water?+

Nearby USGS observations produce an estimate of 321 PPM, or 18.8 grains per gallon, classified as very hard. This is not a household tap measurement.

Do I need a water softener?+

At 321 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.