Sammamish Plateau Water & Sewer
EPA ID: WA5340900 · 79,362 people served · 8 ZIP codes
Even though Sammamish Plateau Water & Sewer accumulated 6 violations over five years, all have been formally resolved — the provider currently meets EPA standards for 79,362 people.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Sammamish Plateau Water & Sewer Source: EPA SDWIS service area boundaries.
Service area boundary — Grade A
Service Area Demographics
The Sammamish Plateau Water & Sewer serves a community with a median household income of $164,058 and an estimated 150,584 residents across its service area.
🌊 Where Does Your Water Come From?
Sammamish Plateau Water & Sewer's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 2% of homes in King County, Washington rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Superfund Proximity Note: This service area ranks in the 70th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Detected Contaminants
How Sammamish Plateau Water & Sewer compares to EPA limits
What This Means For You
Lead at 1 mg/L (action level) exceeds the EPA maximum of 0.015 mg/L (action level). Brain damage in children, kidney & blood pressure in adults. Consider reverse osmosis filtration.
Surface Water Treatment Rule at 3 mg/L exceeds the EPA maximum of mg/L.
Total Organic Carbon at 2 mg/L exceeds the EPA maximum of mg/L.
Consumer Confidence Report Rule at 2 mg/L exceeds the EPA maximum of mg/L.
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 24 detections recorded. 8 exceed federal EPA limits (4 ppt for PFOA/PFOS).
Lead was detected in this water system. reverse osmosis filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
Similar-sized systems in Washington
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
Sammamish Plateau Water & Sewer (EPA ID: WA5340900) is a community water system in Washington that serves approximately 79,362 people from surface water sources.
This system provides water to 8 ZIP codes across 6 communities.
Average Home Safety Score: A (86/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| July 1, 2025 | Surface Water Treatment Rule | Monitoring | Resolved |
| January 1, 2024 | Total Organic Carbon | Monitoring | Resolved |
| October 1, 2023 | Total Organic Carbon | Monitoring | Resolved |
| July 1, 2023 | Surface Water Treatment Rule | Monitoring | Resolved |
| January 1, 2023 | Barium | Monitoring | Resolved |
| January 1, 2023 | Consumer Confidence Report Rule | Monitoring | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Surface Water Treatment Rule | Treatment Failure | 3 | No |
| Total Organic Carbon | Disinfection Byproducts | 2 | No |
| Consumer Confidence Report Rule | Reporting Failure | 2 | No |
| Barium | Inorganic | 1 | No |
| Lead | Inorganic | 1 | No |
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 98014 | 0.0018 mg/L | No | N/A |
| 98074 | 0.0015 mg/L | No | N/A |
| 98075 | 0.0015 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 3 (Low Risk)
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: Service area ZIP codes sourced from EPA Community Water System Service Area Boundaries v3 (March 2026 release). These ZIPs reflect the actual deployment footprint recorded by WA or modeled from parcel and building-footprint data.
- 98014 — Carnation
- 98024 — Fall City
- 98027 — Issaquah
- 98029 — Issaquah
- 98050 — Preston
- 98053 — Redmond
- 98074 — Sammamish
- 98075 — Sammamish
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Sammamish Plateau Water & Sewer (WA5340900) on EPA.gov.
Frequently Asked Questions
Is Sammamish Plateau Water & Sewer water safe to drink?
Sammamish Plateau Water & Sewer has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does Sammamish Plateau Water & Sewer serve?
Sammamish Plateau Water & Sewer serves approximately 79,362 people across 8 ZIP codes in Washington.
Where does Sammamish Plateau Water & Sewer get its water?
The primary water source is surface water.
Contact Your Water Utility
Public-record contact information for the water utility serving this system. Use these channels to request water quality reports, ask about service, or report issues directly.
Contact information from Sammamish Plateau Water and Sewer District Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility, does not act as its agent, and does not provide customer support for it. Contact details shown are public-record information from CCR filings. For service issues, contact the utility directly using the information above.
Water Source & Treatment
Where this water originates and how it's treated before reaching your tap.
Source: Sammamish Plateau Water and Sewer District Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
The State of Washington compiled Source Water Assessment Program (SWAP) data for all community public water systems in the state. The data identifies potential sources of contamination to the water we use for your drinking water.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment chemicals and what each one does
Chemical names are reported verbatim by the utility. Purpose categories are ZipCheckup annotations based on standard drinking-water treatment practice.
Treatment classification and chemical list sourced from Sammamish Plateau Water and Sewer District Consumer Confidence Report.
Treatment intensity is a ZipCheckup-derived classification based on the chemicals and processes the utility reports. Chemicals and contamination sources are taken verbatim from the utility's CCR filing. Routine federal monitoring and contaminant testing shown elsewhere on this page determine whether the water meets safety standards, not the treatment classification.
Federal UCMR5 PFAS Monitoring: Above Current MCL
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). One or more PFAS compounds were measured above the current state-enforceable MCL.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
PFAS Substances Detected in This System
This water system's Consumer Confidence Report disclosed the following PFAS compounds. Levels are from the utility's most recent reporting cycle.
In April 2024, EPA finalized the first National Primary Drinking Water Regulation for six PFAS. Public water systems have until 2029 to comply. EPA — PFAS regulation overview →
Source: Consumer Confidence Report disclosed by Sammamish Plateau Water and Sewer District.
ZipCheckup is not affiliated with this water utility. PFAS detection data is sourced from public Consumer Confidence Reports filed by the utility itself.
Extensive sampling found no lead or copper in any service lines in the SP Water District.
Lead Service Line Replacement Tracker
This water utility's lead service line (LSL) replacement program is tracked from public Consumer Confidence Report filings. Email signup notifies subscribers when the utility files an updated replacement plan or progress milestone.
Sammamish Plateau Water and Sewer District
ZipCheckup is not affiliated with this water utility. LSL replacement-program data is sourced from public CCR filings published by the utility. Subscription notifications are based on automated parsing of subsequent CCR releases.
Learn more about Lead and Copper Rule replacement requirements →
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
This system reports zero confirmed lead service lines in its inventory. Unknown-material counts may still warrant verification.
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
Notable events and violations
This section summarizes events the utility chose to disclose in its most recent Consumer Confidence Report, plus any federal compliance violations the utility recorded against itself. Both lists are utility-authored — ZipCheckup does not audit, judge, or reorder them.
Federal compliance violations on record
These entries are taken verbatim from the utility's CCR violations section. EPA defines four broad violation categories: Maximum Contaminant Level (MCL), Treatment Technique (TT), Monitoring & Reporting (M&R), and Public Notification (PN).
-
monitoring2024-06-21
Seattle Public Utilities experienced a minor monitoring violation for the Cedar Treatment Facility when one part of the monitoring equipment failed to record a portion of data for one of the seven operating ultraviolet (UV) treatment units.
Violations record from Sammamish Plateau Water and Sewer District Consumer Confidence Report.
Notable events from the utility's CCR
These bullet entries are the utility's own narration of operational, regulatory, or infrastructure events during the reporting period.
- The District is nearing approval for construction of a PFAS treatment plant located in Issaquah.
ZipCheckup note: items above reflect what the utility published in its most recent CCR. Federal violation records are also tracked separately by the EPA Safe Drinking Water Information System (SDWIS) — the SDWIS record is the authoritative federal source for any specific regulatory action.
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Sammamish Plateau Water & Sewer (EPA ID: WA5340900) — request the latest Consumer Confidence Report or ask about specific contaminants.