Who supplies Boise’s water
Veolia Water Idaho
EPA system ID ID4010016About 70% groundwater from 81 wells in Boise and Eagle, and about 30% Boise River water treated at the Marden (direct filtration) and Columbia (ultrafiltration membrane) plants.
Boise water report, by the numbers
| What was measured | Result | Federal limit | EWG guideline | Year · source |
|---|---|---|---|---|
| Hardness The report lists hardness in ppm without stating “as CaCO3”. | 13–219 (system average 105) ppm, as reported | No federal limit | — | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Total trihalomethanes (TTHMs) | 45.1 highest running average (range ND–61.6) ppb | 80 ppb | 0.15 ppb | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Haloacetic acids (HAA5) | 38.5 highest running average (range ND–46.7) ppb | 60 ppb | 0.1 ppb | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Arsenic The 14.5 ppb high was a single source result. Compliance is based on running averages; no violation. | 8.6 compliance result (range ND–14.5) ppb | 10 ppb | 0.004 ppb | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Uranium One result exceeded 30 µg/L, but compliance is a running average; no violation. | 21.5 compliance result (range ND–33) µg/L (ppb) | 30 µg/L | — | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Gross alpha (excluding uranium) | 13.8 compliance result pCi/L | 15 pCi/L | — | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Nitrate | 5.9 compliance result (range ND–6.5) ppm | 10 ppm | 0.14 ppm | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Tetrachloroethylene (PCE) | 1.1 compliance result (range ND–2.5) ppb | 5 ppb | 0.06 ppb | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Radium 226 + 228 | 2 compliance result (range ND–2.8) pCi/L | 5 pCi/L | 0.05 pCi/L | 2021Veolia Water Idaho 2025 Consumer Confidence Report |
| Chromium-6 (hexavalent) | 0.429 ppb | No federal limit for chromium-6 (total chromium 100 ppb) | 0.02 ppb | 2021–2023 avgEWG Tap Water Database |
| Lead (90th percentile) One sample was above the action level in September 2025; none in April 2025. | Not detected (April and September 2025 rounds) ppb | 15 ppb action level | — | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Copper (90th percentile) | 0.4 ppm | 1.3 ppm action level | — | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Fluoride Veolia does not add fluoride. | 1.2 compliance result (range 0.2–3; average of all sources 0.4) ppm | 4 ppm (2 ppm secondary standard) | — | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| Chlorine residual | 0.9 highest annual average (range ND–1.6) ppm | 4 ppm MRDL | — | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
| PFOA / PFOS (UCMR5) Other PFAS tested (PFHxS, PFBS, 6:2 FTS) averaged under 1 ppt. | Averages 0.15 / 0.05; single results all below 4 ppt | Listed as unregulated in the report | — | 2024Veolia Water Idaho 2025 Consumer Confidence Report |
| Sodium | 9–59 (system average 28) ppm | No federal limit | — | 2025Veolia Water Idaho 2025 Consumer Confidence Report |
EWG figures are utility annual averages for 2021–2023 (radiological 2018–2023) from tests the utilities report to Idaho DEQ. EWG health guidelines are health-based goals, not legal limits. “ND” means not detected.
Where Boise’s tap water comes from
Veolia blends groundwater from 81 wells in Boise and Eagle (about 70%) with Boise River water (about 30%). River water is treated at the Marden plant, which uses dual-media direct filtration with pH adjustment to reduce corrosivity, and at the Columbia plant, which uses ultrafiltration membranes. Chlorine is added at the wells and both plants.
Because each neighborhood gets a different mix of wells and river water, your hardness, minerals and taste can differ from a friend’s across town. Polyphosphate is added at 13 wells to keep naturally occurring iron and manganese in solution.
What stands out in the 2025 report
- Disinfection byproducts. TTHMs (45.1 ppb) and HAA5 (38.5 ppb) are the highest of the Treasure Valley systems we reviewed. Both are below the federal limits of 80 and 60 ppb.
- Uranium and gross alpha. Uranium’s compliance result was 21.5 µg/L against a 30 µg/L limit, with one individual result of 33. Gross alpha was 13.8 against a limit of 15. Neither was a violation.
- Arsenic. 8.6 ppb compliance result against a 10 ppb limit; one source sample reached 14.5.
- Iron and manganese. Some sources exceeded secondary (aesthetic) guidelines, with iron up to 3,100 ppb and manganese up to 140 ppb in single results. These affect staining and taste, not safety standards.
Is Boise water hard?
It depends on where you live. Veolia’s 2025 report lists hardness from 13 to 219 ppm with a system average of 105 ppm. The report does not say whether those figures are “as calcium carbonate”, which is how hardness is usually rated, so treat them as a range rather than a precise grains-per-gallon number. Homes at the high end of that range typically notice spotting, scale on fixtures and shorter water-heater life.
What treatment actually helps
- Hardness and scale: a whole-home water softener.
- Chlorine taste and odor, and many disinfection byproducts: whole-home activated carbon filtration.
- Drinking and cooking water (arsenic, uranium, nitrate, chromium-6, PFAS): an under-sink reverse osmosis system is the practical point-of-use option.
None of this is required for water that meets federal standards. It’s a choice about taste, scale and how far below the legal limits you want your drinking water to be.
On a private well?
Ada County is served by Central District Health
CDH does not hand out test kits. Its staff collect private-well samples for a fee ($145 collection plus lab fees, July 2026 fee schedule), or you can take a sample to a certified lab yourself. CDH recommends testing well water once a year for bacteria and nitrate.
Treating Boise water
Get an honest recommendation
Tell us what you’re noticing and we’ll recommend only what your water needs, with one written price. If you don’t need a system, we’ll say so.
Frequently asked questions
Is Boise tap water safe to drink?
Who supplies Boise’s water?
Does Boise add fluoride to its water?
Does Boise tap water have PFAS?
How hard is Boise water?
Sources
- Veolia Water Idaho 2025 Consumer Confidence Report
- EWG Tap Water Database, Veolia Water Idaho (ID4010016)
- EPA ECHO, Veolia Water Idaho (ID4010016)
- Veolia Water Idaho, about my water
Honest Water Boise is not affiliated with any utility, Idaho agency or EWG. This guide summarizes public reports for general information and does not replace your utility’s Consumer Confidence Report or a lab test of your own water.
