Is Grimes, CA Tap Water Safe to Drink?
Graded D, with 4 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
48.8/100
waterverge.com Grimes, CA — Water Quality Report
Grimes's drinking water received a grade of D (48.8 out of 100), indicating poor water quality. The city's 1 water system serves approximately 512 residents using groundwater.
Lead levels were measured at 5.8 ppb (90th percentile), which is within EPA limits but above recommended levels. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 71 violations on record, including 61 health-based violations. 4 remain unresolved.
What to know about Grimes's water
Grimes ranks #616 out of 694 cities in California for water quality, placing it among the lowest-rated in the state.
Grimes relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection.
As a small community water system, Grimes may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 20 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Grimes, CA water safe to drink?
Grimes's drinking water has significant quality concerns based on EPA testing data. With a grade of D (48.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 512 residents using groundwater (wells).
Recent water quality updates for Grimes
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Grimes's water quality assessment. Grade: D (48.8/100).
Contaminants: Lead and Copper Rule.
1 health-based. Contaminants: Arsenic.
1 health-based. Contaminants: Arsenic.
Federal disaster declaration (FEMA DR-4683). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3591). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Grimes's water supply.
Within EPA limits but above the American Academy of Pediatrics recommended level of 1 ppb. An NSF 53-certified filter provides additional protection.
Violation history
Grimes's water system has 71 total violations on record, including 61 health-based violations. 4 remain unresolved. 20 violations were issued in the last 5 years.
Flood & environmental risk
Colusa County has experienced 8 federally declared disasters since 1964. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Grimes's water come from?
Grimes's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 512 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Grimes residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Grimes's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Grimes's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Flood & disaster history
Colusa County has experienced 8 federally declared disasters since 1964. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Grimes's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 5.8 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Grimes compares by contaminant
Explore where Grimes ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Grimes's water comes from
Grimes's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by local government ownership and serves approximately 512 people through 1 water system.
Water systems serving Grimes
| System Name | PWSID | Population | Source |
|---|---|---|---|
| COLUSA CO. WWD #1 - GRIMES | CA0600008 | 512 | GW |
How Grimes compares
Full California rankings →Grimes's score of 48.8/100 is below the average of 57/100 among major California cities. It outscores 5 of 10 nearby cities.
Nearby cities
View California rankings →About Grimes, CA
Wikipedia →Grimes is a census-designated place in Colusa County, California on the Southern Pacific Railroad. It lies at an elevation of 46 feet (14 m). The two main roads that run through it are State Route 45 and Grimes-Arbuckle Road. Its ZIP code is 95950, and its area code is 530. Grimes's population was 296 at the 2020 U.S. census.
Learn more about your water
Guides and resources related to Grimes's water quality findings.
Explore water quality across Colusa
Frequently asked questions
Is Grimes, CA tap water safe to drink?
Grimes's water quality earned a grade of D (48.8/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #616 out of 694 cities tested in California.
What contaminants are in Grimes's water?
Lead was measured at 5.8 ppb (90th percentile). 71 violations are on record.
How is Grimes's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Grimes?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Grimes's water come from?
Grimes's water is sourced from Groundwater. The city has 1 water system serving approximately 512 residents.
What health violations has Grimes's water system had?
Grimes has 61 health-based violations on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 4 violations remain unresolved.
Is Grimes's groundwater at risk of contamination?
Grimes uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 71 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Grimes's water compare to other cities?
Grimes ranks #616 out of 694 cities in California (better than 11% of state cities) and #13415 out of 15744 cities nationally (15th percentile). The grade of D reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Grimes's small water system affect quality?
Grimes's system serves approximately 512 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 71 violations on record.