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

ZIP Code 98856 Water Quality & Testing Report

Twisp, WA · Okanogan County County · Updated for 2026

Sahajul HaqueCompiled & verified by Sahajul Haque from official EPA SDWIS records
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 98856 (Twisp, WA)?

Yes, tap water in ZIP code 98856 (Twisp, WA) is safe to drink under EPA Safe Drinking Water Act standards. Supplied by Twisp Town of, the area earns an EPA Safety Grade of B (70/100) with 0 health violations, 1.1 ppb lead, and moderately hard (84 mg/L / 4.9 GPG) water.

Safety Score
B

Water Safety Grade

Good — Minor issues on record

Health Violations

0

Total Violations

1

Lead Risk

Moderate

Contaminants

0

About Tap Water in ZIP Code 98856

Tap water in ZIP code 98856 (Twisp, WA) is distributed by Twisp Town of (EPA ID: WA5390050), serving approximately 1,044 residents. Based on EPA Safe Drinking Water Act compliance records, this system receives a water safety grade of B with a composite quality score of 70/100.

Water System

Twisp Town of

EPA ID: WA5390050

Water Source

Ground Water

Population Served

1,044 residents

County

Okanogan County County, Washington

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Lead Levels in ZIP 98856

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

Lead Level: 1.1 ppb — Very Low

The 90th percentile lead level in 98856 is 1.1 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 98856 is rated Moderate. EPA models estimate a 39% exposure probability based on housing and infrastructure age.

Lead Level (90th percentile)
1.10 ppb (0.0011 mg/L)
Lead Exposure Risk Rating
Moderate
Lead Exposure Probability

EPA model estimate based on housing age and infrastructure

39%
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: Moderately Hard4.9 GPG · 84 mg/L

Water in ZIP 98856 is Moderately Hard (84 mg/L / 4.9 GPG). It contains beneficial natural minerals like calcium and magnesium without causing heavy scale accumulation.

Recommendation: A water softener is optional. Regular maintenance of hot water appliances is recommended.
Hardness (GPG)

Grains per gallon

4.9 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

84 mg/L
Appliance Scaling Risk
Low / Moderate

Official EPA SDWIS Database Entry

Utility: Twisp Town of · PWSID: WA5390050

Verify on EPA.gov
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Violation History

Past 5 years — EPA SDWIS data

Twisp Town of has recorded 1 violation, but none are health-based (e.g., administrative or monitoring infractions).

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

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

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Contaminants Detected

Contaminants with health-based violations on record

No health-based contaminant violations are on record for ZIP code 98856 under the Safe Drinking Water Act.

⚖ Enforcement Actions

EPA or state regulators have issued 1 enforcement action 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

5.71%

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 98856

Tap Water & Well Testing Recommendations

Residents in ZIP code 98856 served by Twisp Town of 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 Washington State Department of Health.
Certified Lab Testing: Always use an EPA-certified drinking water laboratory in WA for formal legal or real estate compliance testing.

🛡 What Should You Do? — ZIP 98856 Recommendations

  • ✓ Run cold water for 30 seconds each morning before use — especially if pipes are old
  • ✓ Request your annual Consumer Confidence Report from Twisp Town of
  • ✓ If your home was built before 1986, consider testing your own tap for lead
  • ✓ Use a pitcher filter (NSF/ANSI 42 certified) for improved taste

Recommended Taste & Safety Filter:

🚰

NSF/ANSI 53 Certified Pitcher Filter

Best for removing aesthetic chlorine, odors, and low-level heavy metals.

Filter Selection Guide →

Frequently Asked Questions — ZIP 98856 Water Quality

Is tap water safe to drink in ZIP code 98856?+
Yes — tap water in 98856 (Twisp, WA) meets EPA standards with a water safety grade of B. No health-based violations are on record in the past 5 years.
How do I get my water tested in ZIP 98856 (Twisp, WA)?+
To test water quality in ZIP 98856, you can order a certified drinking water test kit or send water samples to an EPA/NELAP certified laboratory in WA. Certified testing checks for lead, coliform bacteria, nitrates, hardness, and PFAS that standard test strips miss. Contact Washington State Department of Health for a list of certified regional labs.
How hard is the tap water in 98856?+
Tap water in 98856 is classified as Moderately Hard with an estimated mineral hardness of 84 mg/L (4.9 GPG). A water softener is optional. Regular maintenance of hot water appliances is recommended.
Should I test private well water in 98856?+
Yes. Unlike municipal systems, private wells in 98856 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 98856 tap water?+
The 90th percentile lead level in 98856 is 1.1 ppb. The EPA action level is 15 ppb. This is below the EPA action level.
Is there an active boil water notice in 98856?+
There are currently no active boil water advisories on record for 98856. Water treatment systems are operating within normal parameters.
Who provides tap water to 98856?+
Tap water in ZIP code 98856 is provided by Twisp Town of (EPA ID: WA5390050), serving approximately 1,044 residents.
What water filter should I use in 98856?+
Based on water metrics for 98856, we recommend None / Standard Pitcher. Look for certifications such as NSF/ANSI 42 (Chlorine, Taste & Odor).

Data Sources & Methodology

Water quality data for ZIP code 98856 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 Twisp Town of. 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 →