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Official EPA SDWIS Verified ReportWater Quality & Testing GuideHistorical Record: No Recorded SDWIS Violations

ZIP Code 59631 Water Quality & Testing Report

Basin, MT · Jefferson County County · Updated for 2026

Public Health & Medical Notice: Drinking water quality data on this page reflects historical compliance records submitted under the Safe Drinking Water Act. This information does not constitute medical advice or a real-time safety guarantee. If you are pregnant, nursing, preparing infant formula, or immunocompromised, consult a healthcare provider. Boiling water kills biological pathogens, but does NOT remove chemical contaminants like lead, arsenic, or PFAS.
Quick EPA Verified Answer

Is Tap Water Safe to Drink in ZIP 59631 (Basin, MT)?

Caution / Filtration Recommended: Tap water in ZIP code 59631 (Basin, MT) has compliance concerns, earning an EPA Safety Grade of C (69/100) due to 1 health violation(s) and 1.0 ppb lead. While treated by Basin County Water and Sewer District, residents are advised to use an NSF/ANSI 53 certified water filter for drinking and cooking.

Safety Score
C

Water Safety Grade

Fair — Some compliance concerns

Health Violations

1

Total Violations

9

Lead Risk

Moderate

Contaminants

1

About Tap Water in ZIP Code 59631

Tap water in ZIP code 59631 (Basin, MT) is distributed by Basin County Water and Sewer District (EPA ID: MT0000014), serving approximately 200 residents. Based on EPA Safe Drinking Water Act compliance records, this system receives a water safety grade of C with a composite quality score of 69/100.

Water System

Basin County Water and Sewer District

EPA ID: MT0000014

Water Source

Ground Water

Population Served

200 residents

County

Jefferson County County, Montana

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Lead Levels in ZIP 59631

EPA action level: 15 ppb | Public health goal: 0 ppb

Lead Level: 1.0 ppb — Very Low

The 90th percentile lead level in 59631 is 1.0 ppb. This meets the EPA action level of 15 ppb. Health experts recommend a target of 0 ppb for optimal safety.

Lead exposure risk in 59631 is rated Moderate. EPA models estimate a 44% exposure probability based on housing and infrastructure age.

Lead Level (90th percentile)
1.00 ppb (0.001 mg/L)
Copper Level (90th percentile)

EPA action level: 1.3 mg/L

1.76 mg/L
Lead Exposure Risk Rating
Moderate
Lead Exposure Probability

EPA model estimate based on housing age and infrastructure

44%
Note: Lead levels above are the 90th percentile from EPA monitoring — meaning 90% of samples were at or below this level. Even "undetected" tap water lead doesn't account for lead leaching from home plumbing. If your home was built before 1986, individual tap testing is recommended.
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Water Hardness & Mineral Content

Grains per gallon (GPG) & Parts per million (PPM / mg/L)

Classification: Very Hard14 GPG · 239 mg/L

Water in ZIP 59631 is Very Hard (239 mg/L / 14 GPG). High concentrations of dissolved limestone minerals cause severe mineral buildup, stiff laundry, dry skin, and premature water heater wear.

Recommendation: A whole-home water softener system is strongly recommended to protect plumbing and home appliances.
Hardness (GPG)

Grains per gallon

14 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

239 mg/L
Appliance Scaling Risk
High / Severe

Official EPA SDWIS Database Entry

Utility: Basin County Water and Sewer District · PWSID: MT0000014

Verify on EPA.gov
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Violation History

Past 5 years — EPA SDWIS data

Basin County Water and Sewer District has recorded 1 health-based violation out of 9 total violations over the past 5 years.

Total Violations (5 yr)
9
Health-Based Violations
1
Unresolved Violations
0
Boil Water Advisories
0
Compliance Risk
High

Regulatory compliance risk for this utility is rated High based on past reporting and enforcement records.

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Contaminants Detected

Contaminants with health-based violations on record

EPA records identify 1 contaminant with health-based violations in the past 5 years: Stage 1 DBP Rule.

Stage 1 DBP Rule

⚖ Enforcement Actions

EPA or state regulators have issued 10 enforcement actions to address compliance lapses.
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Water Source & Environmental Factors

Ground Water

This system draws water from underground aquifers. Groundwater is naturally filtered through soil and rock, but can still contain naturally occurring minerals like arsenic, radium, or nitrates.

Water Source Type
Ground Water
EPA Radon Zone

Highest potential

Zone 1
Annual Flood Risk Cost

Estimated annual flood-related costs per property

$0
Energy Burden

% of household income spent on energy — indicator of older infrastructure

3.18%

EPA Radon Zone 1 — highest potential for radon in indoor air. Homeowners should test their home for radon and consider mitigation if levels exceed 4 pCi/L.

Water Quality Testing in ZIP 59631

Tap Water & Well Testing Recommendations

Residents in ZIP code 59631 served by Basin County Water and Sewer District can test tap water or private well systems to verify water purity. Testing detects hidden contaminants before they impact family health.

Tap Water Testing Steps

  • 1.Conduct a certified lead check if your home was constructed before 1986.
  • 2.Use certified lab testing kits rather than uncalibrated test strips for regulated compliance.
  • 3.Sample water from both your kitchen faucet and water heater to compare line purity.

Private Well Testing Steps

  • •Test for Coliform bacteria and Nitrates annually.
  • •Test for heavy metals, radon, and PFAS every 3 years.
  • •Send samples to a state-certified drinking water laboratory recognized by Montana Department of Environmental Quality.
Certified Lab Testing: Always use an EPA-certified drinking water laboratory in MT for formal legal or real estate compliance testing.

🛡 What Should You Do? — ZIP 59631 Recommendations

  • ⚠ Use a certified NSF/ANSI 53 filter for drinking and cooking water if you have young children
  • ⚠ Never give unfiltered tap water to infants in formula — use certified bottled or filtered water
  • ⚠ Request a copy of the Consumer Confidence Report to see what was detected and when
  • ⚠ Call the EPA Safe Drinking Water Hotline: 1-800-426-4791

Recommended Water Treatment Systems:

🏺

NSF 53 Lead Pitcher Filter

Specifically certified to reduce lead and copper at the tap.

Lead Filter Guide →
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NSF 58 Under-Sink RO System

Advanced filtration for PFAS, fluoride, nitrates, and organic chemicals.

RO System Guide →

Frequently Asked Questions — ZIP 59631 Water Quality

Is tap water safe to drink in ZIP code 59631?+
Tap water in 59631 (Basin, MT) meets major standards but has a grade of C due to minor past violations. Vulnerable populations may want to use a certified filter as a precaution.
How do I get my water tested in ZIP 59631 (Basin, MT)?+
To test water quality in ZIP 59631, you can order a certified drinking water test kit or send water samples to an EPA/NELAP certified laboratory in MT. Certified testing checks for lead, coliform bacteria, nitrates, hardness, and PFAS that standard test strips miss. Contact Montana Department of Environmental Quality for a list of certified regional labs.
How hard is the tap water in 59631?+
Tap water in 59631 is classified as Very Hard with an estimated mineral hardness of 239 mg/L (14 GPG). A whole-home water softener system is strongly recommended to protect plumbing and home appliances.
Should I test private well water in 59631?+
Yes. Unlike municipal systems, private wells in 59631 are not regulated by the EPA or local utilities. Private well owners should test their water annually for coliform bacteria and nitrates, and every 3 to 5 years for heavy metals (lead, arsenic) and volatile organic compounds.
What is the lead level in 59631 tap water?+
The 90th percentile lead level in 59631 is 1.0 ppb. The EPA action level is 15 ppb. This is below the EPA action level.
Is there an active boil water notice in 59631?+
There are currently no active boil water advisories on record for 59631. Water treatment systems are operating within normal parameters.
Who provides tap water to 59631?+
Tap water in ZIP code 59631 is provided by Basin County Water and Sewer District (EPA ID: MT0000014), serving approximately 200 residents.
What water filter should I use in 59631?+
Based on water metrics for 59631, we recommend Reverse Osmosis (PFAS & Lead). Look for certifications such as NSF/ANSI 53 (Chemical Contaminants), NSF/ANSI 42 (Aesthetic Effects).

Data Sources & Methodology

Water quality data for ZIP code 59631 is compiled from the EPA Safe Drinking Water Information System (SDWIS), EPA ECHO enforcement database, UCMR5 unregulated contaminant monitoring, and Consumer Confidence Reports filed by Basin County Water and Sewer District. Safety scores are composite metrics derived from violation history, lead levels, enforcement actions, and infrastructure risk indicators. Data reflects a 5-year monitoring window. Last dataset update: 2024. View EPA source data →