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

ZIP Code 98133 Water Quality & Testing Report

Seattle, WA · King 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 98133 (Seattle, WA)?

Yes, tap water in ZIP code 98133 (Seattle, WA) is safe to drink under EPA Safe Drinking Water Act standards. Supplied by Seattle Public Utilities, the area earns an EPA Safety Grade of A (90/100) with 0 health violations, 3.5 ppb lead, and soft (51 mg/L / 3 GPG) water.

Safety Score
A

Water Safety Grade

Excellent — Meets all EPA standards

Health Violations

0

Total Violations

1

Lead Risk

High

Contaminants

0

About Tap Water in ZIP Code 98133

Tap water in ZIP code 98133 (Seattle, WA) is distributed by Seattle Public Utilities (EPA ID: WA5377050), serving approximately 1,091,904 residents. Based on EPA Safe Drinking Water Act compliance records, this system receives a water safety grade of A with a composite quality score of 90/100.

Water System

Seattle Public Utilities

EPA ID: WA5377050

Water Source

Surface Water

Population Served

1,091,904 residents

County

King County County, Washington

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Lead Levels in ZIP 98133

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

Lead Level: 3.5 ppb — Very Low

The 90th percentile lead level in 98133 is 3.5 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 98133 is rated High. EPA models estimate a 49% exposure probability based on housing and infrastructure age.

Lead Level (90th percentile)
3.50 ppb (0.0035 mg/L)
Lead Exposure Risk Rating
High
Lead Exposure Probability

EPA model estimate based on housing age and infrastructure

49%
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: Soft3 GPG · 51 mg/L

Water in ZIP 98133 is classified as Soft (51 mg/L / 3 GPG). Soft water produces abundant soap lather, prevents scale buildup in water heaters, and does not leave spots on dishes.

Recommendation: No water softener is needed. Standard carbon filtration is sufficient for taste and chlorine reduction.
Hardness (GPG)

Grains per gallon

3 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

51 mg/L
Appliance Scaling Risk
Very Low

Official EPA SDWIS Database Entry

Utility: Seattle Public Utilities · PWSID: WA5377050

Verify on EPA.gov
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Violation History

Past 5 years — EPA SDWIS data

Seattle Public Utilities 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
Low

Regulatory compliance risk for this utility is rated Low 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 98133 under the Safe Drinking Water Act.

From Consumer Confidence Report:

Turbidity (5 NTU*)

⚖ Enforcement Actions

EPA or state regulators have issued 1 enforcement action to address compliance lapses.
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Water Source & Environmental Factors

Surface Water

This system draws water from lakes, rivers, or reservoirs. Surface water is treated to remove sediment, microorganisms, and chemical contaminants before reaching taps.

Water Source Type
Surface Water
CCR Source Classification
Surface Water and Ground Water
EPA Radon Zone

Lower potential

Zone 3
Annual Flood Risk Cost

Estimated annual flood-related costs per property

$0
Energy Burden

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

2.9%

EPA Radon Zone 3 — lower radon potential, though the EPA still recommends testing all homes.

Water Quality Testing in ZIP 98133

Tap Water & Well Testing Recommendations

Residents in ZIP code 98133 served by Seattle Public Utilities 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 98133 Recommendations

  • ✓ Run cold water for 30 seconds each morning before use — especially if pipes are old
  • ✓ Request your annual Consumer Confidence Report from Seattle Public Utilities
  • ✓ 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 98133 Water Quality

Is tap water safe to drink in ZIP code 98133?+
Yes — tap water in 98133 (Seattle, WA) meets EPA standards with a water safety grade of A. No health-based violations are on record in the past 5 years.
How do I get my water tested in ZIP 98133 (Seattle, WA)?+
To test water quality in ZIP 98133, 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 98133?+
Tap water in 98133 is classified as Soft with an estimated mineral hardness of 51 mg/L (3 GPG). No water softener is needed. Standard carbon filtration is sufficient for taste and chlorine reduction.
Should I test private well water in 98133?+
Yes. Unlike municipal systems, private wells in 98133 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 98133 tap water?+
The 90th percentile lead level in 98133 is 3.5 ppb. The EPA action level is 15 ppb. This is below the EPA action level.
Is there an active boil water notice in 98133?+
There are currently no active boil water advisories on record for 98133. Water treatment systems are operating within normal parameters.
Who provides tap water to 98133?+
Tap water in ZIP code 98133 is provided by Seattle Public Utilities (EPA ID: WA5377050), serving approximately 1,091,904 residents.
What water filter should I use in 98133?+
Based on water metrics for 98133, we recommend Lead & Microplastic Filter. Look for certifications such as NSF/ANSI 53 (Lead Reduction), NSF/ANSI 42 (Particulate/Taste).

Data Sources & Methodology

Water quality data for ZIP code 98133 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 Seattle Public Utilities. 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 →