Is Twin Falls, ID tap water safe?
Supplied by City of Twin Falls · serves 56,121 people (19,273 connections) · Groundwater · EPA ID ID5420058
Data: U.S. EPA · How we read the data · How we check it
Summary
No federal limits exceeded in EPA data.
- PFAS
- Not detectedNone of 29 PFAS found above EPA's reporting limits in 3 samples (2023–2025).
- Lithium
- Above screening levelHighest result 47.7 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 level0 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 ending Jun 2026. 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 Twin Falls'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) 736-1540. EPA: how to find it.
PFAS (“forever chemicals”)
EPA UCMR 5: 2 entry points tested Nov 2024 to Mar 2026. "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 4 of 4 samples. Highest result 47.7 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: 0 ppb lead (Jan 2026 – Jun 2026). Below action level
Highest since 2016: 2 ppb (Dec 2016).
| Monitoring period | Lead (90th pct.) |
|---|---|
| Jan 2026 – Jun 2026 | 0 ppb |
| Jul 2025 – Dec 2025 | 0 ppb |
| Jan 2025 – Jun 2025 | 0 ppb |
Earlier results (9)
| Jul 2024 – Dec 2024 | 1 ppb |
| Jan 2024 – Jun 2024 | 0 ppb |
| Jul 2023 – Dec 2023 | 0 ppb |
| Jan 2023 – Jun 2023 | 0 ppb |
| Jul 2022 – Dec 2022 | 0 ppb |
| Jan 2022 – Jun 2022 | 0 ppb |
| Jan 2017 – Dec 2019 | 1 ppb |
| Jan 2014 – Dec 2016 | 2 ppb |
| Jan 2011 – Dec 2013 | 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 |
|---|---|---|
| Vanadium | 31.3 ppb | 21 ppb |
| Molybdenum | 3.43 ppb | 40 ppb |
| Chlorate | 93 ppb | 210 ppb |
| Chromium-6 | 3.01 ppb | – |
| Strontium | 0.51 ppm | 1.5 ppm |
Where it serves
Twin Falls
ZIP codes the system reported serving: 83301, 83303
Nearby utilities
- City of Pocatello Pocatello · 104 mi
- Capitol Water Corp Boise City · 115 mi · PFAS above limit
- Veolia Water Idaho Boise City · 115 mi
- Garden City Water and Sewer System Garden City · 120 mi · PFAS above limit
- Meridian Water Dept Meridian · 122 mi
- City of Nampa Nampa · 128 mi
Questions
Is Twin Falls tap water safe to drink?
Most of Twin Falls gets its water from City of Twin Falls. City of Twin Falls 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 Twin Falls water have PFAS?
EPA tested City of Twin Falls for 29 PFAS between Nov 2024 and Mar 2026 and none were detected above the reporting limits (about 2 to 20 ppt depending on the chemical).
What is the lead level in Twin Falls water?
The most recent 90th-percentile lead result for City of Twin Falls is 0 ppb, for the period ending Jun 2026. 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 ID5420058: violations, enforcement and inspections, straight from EPA.
- EPA UCMR 5 data: the PFAS and lithium results (search the file for PWSID ID5420058).
- 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 Twin Falls at (208) 736-1540, 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.