Is Nampa, ID tap water safe?
Supplied by City of Nampa · serves 100,200 people (38,361 connections) · Groundwater · EPA ID ID3140080
Data: U.S. EPA · How we read the data · How we check it
Most of Nampa gets its water from City of Nampa. Parts of the city are served by 2 smaller systems: Southshore Water (60 people), Valley View Water (57 people). Your water bill names your system.
Summary
No federal limits exceeded in EPA data.
- PFAS
- Not detectedNone of 29 PFAS found above EPA's reporting limits in 26 samples (2023–2025).
- Lithium
- Above screening levelHighest result 42.1 ppb. EPA uses 10 ppb to decide what to study further. It is not a health limit, and there is no federal limit for lithium. About 1 in 4 systems tested were above it.
- Lead
- Below action level1 ppb (parts per billion) at the 90th percentile: 9 in 10 homes sampled were at or below it. Action level 15 ppb, falling to 10 ppb in Nov 2027. Monitoring period Jan 2025 – now, still in progress (results reported so far). Your home's pipes can make yours higher.
- Violations
- None health-basedNo health-based violations since 2016.
- Built before 1986, or not sure what your service line is made of? Check your service line and test your tap. Utility data can't show your pipes.
- Tested your own tap? Compare your result with these numbers. Moving? Compare this system with another.
- Read City of Nampa's annual water quality report (Consumer Confidence Report). It lists every regulated contaminant tested and is usually on the utility's website or mailed with your bill, and you can also request it at (208) 468-5860. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 13 entry points tested Jul 2024 to Dec 2025. "Average" is the highest entry-point average (non-detects counted as zero), the way EPA compares UCMR 5 results to the limits. ppt = parts per trillion. These results do not determine compliance.
| Contaminant | Highest average |
|---|---|
| PFOA Not detected Limit 4 ppt | – |
| PFOS Not detected Limit 4 ppt | – |
| PFHxS Not detected Limit 10 ppt | – |
| PFNA Not detected Limit 10 ppt | – |
| HFPO-DA (GenX) Not detected Limit 10 ppt | – |
| Hazard Index (a combined score for PFHxS, PFNA, GenX and PFBS, where above 1 is over the limit) Not detected Limit 1 | – |
| PFBS Not detected Guideline 2,000 ppt | – |
| PFBA Not detected Guideline 6,000 ppt | – |
| PFHxA Not detected Guideline 3,000 ppt | – |
29 PFAS tested, 0 detected at least once. "Not detected" means below EPA's reporting limit (about 2 to 20 ppt depending on the chemical), not proven zero. PFAS not listed were not detected. The limits for PFHxS, PFNA, GenX and the Hazard Index were proposed for rescission in May 2026. That proposal is not final. Systems have until 2029 to meet the limits.
Lithium
Detected in 26 of 26 samples. Highest result 42.1 ppb. EPA's non-enforceable screening level is 10 ppb. Above screening level The screening level is how EPA decides what to study further, not a health limit. There is no federal limit for lithium and no filter is certified to remove it. About lithium.
Lead and copper
Latest 90th percentile: 1 ppb lead (Jan 2025 – now (in progress)). Below action level
Highest since 2016: 2 ppb (Dec 2024).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2025 – now (in progress) | 1 ppb |
| Jan 2022 – Dec 2024 | 2 ppb |
| Jan 2019 – Dec 2021 | 0 ppb |
Earlier results (9)
| Jan 2018 – Dec 2018 | 0 ppb |
| Jul 2017 – Dec 2017 | 0 ppb |
| Jan 2017 – Jun 2017 | 0 ppb |
| Jul 2016 – Dec 2016 | 0 ppb |
| Jan 2011 – Dec 2013 | 0 ppb |
| Jan 2009 – Dec 2011 | 1.7 ppb |
| Jan 2006 – Dec 2008 | 2.1 ppb |
| Jan 2003 – Dec 2005 | 3 ppb |
| Jan 1998 – Dec 2000 | 0 ppb |
Lead comes from pipes and fixtures, not the source water, so it varies home to home. The 90th percentile means 9 in 10 sampled homes were at or below it. More on lead.
Violations
Health-based violations mean a contaminant exceeded a limit or a required treatment step was missed. Monitoring and reporting violations mean required tests or reports were late or missing, so the water's quality during that time is unknown. The total includes every violation in EPA's records, most of them paperwork.
Earlier EPA testing (2013–2020)
| Contaminant | Highest | Guideline |
|---|---|---|
| Manganese | 31.4 ppb | 300 ppb |
| Chromium-6 | 6.16 ppb | – |
| Strontium | 0.5 ppm | 1.5 ppm |
| Vanadium | 31.8 ppb | 21 ppb |
| Molybdenum | 7.51 ppb | 40 ppb |
| Chlorate | 26.5 ppb | 210 ppb |
Where it serves
Nampa
ZIP codes the system reported serving: 83651, 83652, 83653, 83686, 83687
Nearby utilities
- City of Caldwell Caldwell · 6 mi
- Meridian Water Dept Meridian · 9 mi
- Garden City Water and Sewer System Garden City · 15 mi · PFAS above limit
- Capitol Water Corp Boise City · 17 mi · PFAS above limit
- Veolia Water Idaho Boise City · 17 mi
- City of Twin Falls Twin Falls · 126 mi
Questions
Is Nampa tap water safe to drink?
Most of Nampa gets its water from City of Nampa. City of Nampa has no health-based violations since 2016. EPA testing found no PFAS above the federal limits. Federal data can't tell you about your own pipes: lead comes from service lines and plumbing, so test your tap if your home was built before 1986. For the official word, read the utility's annual Consumer Confidence Report.
Does Nampa water have PFAS?
EPA tested City of Nampa for 29 PFAS between Jul 2024 and Dec 2025 and none were detected above the reporting limits (about 2 to 20 ppt depending on the chemical).
What is the lead level in Nampa water?
The most recent 90th-percentile lead result for City of Nampa is 1 ppb, for the monitoring period that began Jan 2025 (still in progress). The federal action level is 15 ppb, falling to 10 ppb in November 2027. The 90th percentile means 9 in 10 homes sampled were at or below this number. Individual homes can be higher.
Check these numbers yourself
Every figure on this page comes from public EPA records. You don't have to take our word for it:
- EPA's own report for ID3140080: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID ID3140080).
- EPA SDWIS download: the lead results, population and violation records we use.
- The utility's annual water quality report (Consumer Confidence Report): ask City of Nampa at (208) 468-5860, or see EPA's guide to finding it.
Found something that doesn't match? Tell us and we'll check it against EPA's records. How we check our data.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.