City of Rohnert Park
EPA ID: CA4910014 · 43,821 people served · 9 ZIP codes
In the most recent five-year monitoring window, City of Rohnert Park posted zero EPA violations serving 43,821 residents.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for City of Rohnert Park Source: EPA SDWIS service area boundaries.
Service area boundary — Grade A
Service Area Demographics
The City of Rohnert Park serves a community with a median household income of $103,105 and an estimated 210,202 residents across its service area. Approximately 62% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
💧 Where Does Your Water Come From?
City of Rohnert Park's water is pumped from underground aquifers. Groundwater is naturally filtered through rock and soil, but it can be vulnerable to PFAS contamination, nitrates from agriculture, and industrial chemicals that seep into the water table.
About 1% of homes in Sonoma County, California rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 3 detections recorded. 1 exceeds federal EPA limits (4 ppt for PFOA/PFOS).
Comparable Water Systems
Similar-sized systems in California
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
City of Rohnert Park, (EPA ID: CA4910014) is a community water system in California that serves approximately 43,821 people from groundwater sources.
This system provides water to 9 ZIP codes across 5 communities.
Average Home Safety Score: A (94/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 94926 | 0.0061 mg/L | No | N/A |
| 94927 | 0.0061 mg/L | No | N/A |
| 94928 | 0.0061 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: 7 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 2 additional ZIPs inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
- 94926 — Rohnert Park
- 94927 — Rohnert Park
- 94928 — Rohnert Park
- 94931 — Cotati
- 94951 — Penngrove
- 94952 — Petaluma
- 94954 — Petaluma
- 95404 — Santa Rosa
- 95407 — Santa Rosa
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for City of Rohnert Park (CA4910014) on EPA.gov.
Frequently Asked Questions
Is City of Rohnert Park water safe to drink?
Based on EPA records, City of Rohnert Park has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does City of Rohnert Park serve?
City of Rohnert Park serves approximately 43,821 people across 9 ZIP codes in California.
Where does City of Rohnert Park get its water?
The primary water source is groundwater.
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 City of Rohnert Park 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: City of Rohnert Park Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
According to the Drinking Water Source Assessment Plan, our water sources are most vulnerable to the following activities: chemical/petroleum storage, pesticide/fertilizer used in association with parks and golf courses, transportation corridors, storm drain discharge points, stormwater detention facilities, agricultural drainage, golf course ponds, high-density housing, and utility stations.
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.
Watershed exposure sources reported
Land-use and natural conditions identified in the utility's source-water assessment as potential contamination sources upstream of treatment.
Treatment classification and chemical list sourced from City of Rohnert Park 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: Detected
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). PFAS compounds were detected below 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 →
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.
Aesthetic water quality
These measurements describe the look, taste, and feel of the water this utility delivers. They are not contaminant violations — they sit alongside federal Secondary Maximum Contaminant Levels (SMCLs) which the EPA publishes as non-enforceable guidance.
Aesthetic measurements from City of Rohnert Park Consumer Confidence Report.
Aesthetic measurements are reported by the utility from its annual sampling. EPA Secondary MCLs are advisory thresholds — values outside them indicate aesthetic concerns such as taste or appearance, not health violations. Federal contaminant testing is shown in the sections above.
Hard water detected in City of Rohnert Park
Your utility reported water hardness of 209 ppm CaCO₃ (12.2 grains per gallon) in its most recent Consumer Confidence Report. This is in the hard range and may cause scale buildup, reduced appliance lifespan, and dry skin or hair.
There are three common approaches to treating hard water: salt-based ion-exchange softeners (most effective, require salt refills), salt-free conditioners (lower maintenance, scale prevention only), and reverse osmosis at the kitchen sink (cooking and drinking water only). Aquasana, EcoWater, Pelican, and SpringWell are among the major US brands.
Paid Partner. ZipCheckup earns commission on Aquasana purchases. We do not test water or verify product effectiveness for specific hardness levels — manufacturer claims are theirs alone. Consult a certified water-quality professional for personalized advice.
Hardness data parsed from this utility's most recent Consumer Confidence Report. Severity bands per USGS hard water classification.