City of Mountain Home water quality
Met every federal limit. 1 contaminant at half a limit or higher. hardness not in the latest CCR.
ID4200032. Data through 2026-08-26. DEQ record.
What's in it
Arsenic
ElevatedBrondell Circle RC100 Reverse Osmosis System is certified to reduce it.
15 other contaminants tested, not detected or well below the limit
Copper 0.02ppm Fluoride 0.38ppm Gross Alpha ND Haloacetic Acids (HAA5) 5.6ppb HFPO-DA (GenX) ND Lead ND Nitrate (as N) 2.40ppm PFBS ND PFHxS ND PFNA ND PFOA ND PFOS ND Radium 226 + 228 ND Total Trihalomethanes 17.6ppb Uranium ND
Filters that match
Brondell Circle RC100 Reverse Osmosis System
under sink ro · diy
- Arsenicremoves it, NSF or WQA certified
Nothing in this water calls for whole-house treatment. A drinking-water filter covers the exposure that matters. Whole-house units here are optional, mainly for taste and chlorine.
Detections ranked by share of the limitevery Tier 1 detection, highest first
Bar length is the highest result in the last 36 months as a share of the federal limit (MCL, or action level for lead and copper). The dark tick marks the limit. Gross alpha is compared after subtracting uranium, as DEQ does for compliance.
Full contaminants reporthighest, latest, limit, trend, last sample
| Contaminant | Highest, 36 mo | Federal limit | Share of limit | Status | Trend | Last sample |
|---|---|---|---|---|---|---|
| Arsenic | 3.1ppb | 10.0ppb MCL | Elevated | 2025-09-30 | ||
| Copper 90th percentile at home taps note | 0.02ppm latest 0.02ppm | 1.30ppm AL | Detected | 2025-12-31 | ||
| Fluoride | 0.38ppm | 4.00ppm MCL | Detected | 2025-09-30 | ||
| Gross Alpha | ND | 15.0pCi/L MCL | Not detected | 2025-09-30 | ||
| Haloacetic Acids (HAA5) | 5.6ppb | 60.0ppb MCL | Detected | 2025-08-13 | ||
| HFPO-DA (GenX) | ND | 10.0ppt MCL | Not detected | 2026-06-25 EPA study | ||
| Lead 90th percentile at home taps note | 0.0ppb | 15.0ppb AL | Not detected | 2025-12-31 | ||
| Nitrate (as N) | 2.40ppm latest 0.90ppm | 10.00ppm MCL | Detected | 2026-08-26 | ||
| PFBS | ND | none | Not detected | 2025-10-17 EPA study | ||
| PFHxS | ND | 10.0ppt MCL | Not detected | 2026-06-25 EPA study | ||
| PFNA | ND | 10.0ppt MCL | Not detected | 2025-10-17 EPA study | ||
| PFOA | ND | 4.0ppt MCL | Not detected | 2025-10-17 EPA study | ||
| PFOS | ND | 4.0ppt MCL | Not detected | 2025-10-17 EPA study | ||
| Radium 226 + 228 | 1.19pCi/L latest ND | 5.00pCi/L MCL | Detected | 2025-09-30 | ||
| Total Trihalomethanes | 17.6ppb latest 1.2ppb | 80.0ppb MCL | Detected | 2025-08-13 | ||
| Uranium | ND | 30.0ppb MCL | Not detected | 2025-09-30 |
- Copper: 90th percentile of samples taken at customer taps. Results depend on the home's plumbing.
- Lead: 90th percentile of samples taken at customer taps. Results depend on the home's plumbing.
ppb = parts per billion (µg/L), ppm = parts per million (mg/L), ppt = parts per trillion. ND = not detected above the lab's reporting limit. MCL = federal maximum contaminant level; AL = action level for lead and copper (90th percentile of home taps); aesthetic = secondary standard for taste, odor or staining, not health. Bars show the highest result in 36 months as a share of the limit.
15 other regulated contaminants tested
| Contaminant | 36 mo max | Limit | Status | Last sample |
|---|---|---|---|---|
| Antimony | ND | 6.0ppb | Not detected | 2025-09-30 |
| Atrazine | ND | 3.0ppb | Not detected | 2026-06-25 |
| Barium | ND | 2.00ppm | Not detected | 2025-09-30 |
| Benzene | ND | 5.0ppb | Not detected | 2025-09-30 |
| Beryllium | ND | 4.0ppb | Not detected | 2025-09-30 |
| Cadmium | ND | 5.0ppb | Not detected | 2025-09-30 |
| Chromium (total) | 0.00ppm | 0.10ppm | Detected | 2025-09-30 |
| 1,2-Dibromo-3-chloropropane | ND | 0.2ppb | Not detected | 2025-12-29 |
| Lithium | ND | none | Not detected | 2025-10-17 |
| Mercury (inorganic) | ND | 2.0ppb | Not detected | 2025-09-30 |
| Tetrachloroethylene | ND | 5.0ppb | Not detected | 2025-09-30 |
| Selenium | ND | 50.0ppb | Not detected | 2025-09-30 |
| Sodium | 17.70ppm | none | Detected | 2025-09-30 |
| Trichloroethylene | ND | 5.0ppb | Not detected | 2025-09-30 |
| Thallium | ND | 2.0ppb | Not detected | 2025-09-30 |
Hardness
Hardness is not reported in the latest CCR. Hardness not reported for this system; softener sizing uses a regional default of 11.7 gpg until a CCR value is reviewed.
See also Mountain Home water hardness.
Track record153 violations on record, 3 health-based
✓ no violation recorded n monitoring or reporting only n includes a health-based violation ? outside the loaded record
Health-based violations
| Period | What happened | Contaminant | Rule | Status |
|---|---|---|---|---|
| 2025-08-01 | Treatment technique not met (Reporting, routine (RTCR)) | n/a | Revised Total Coliform Rule | resolved 2025-12-11 |
| 2024-10-17 | Treatment technique not met (Level 2 assessment, treatment technique (RTCR)) | n/a | Lead and Copper Rule Revisions | resolved 2025-01-23 |
| 2017-08-12 | Treatment technique not met (Reporting, routine (RTCR)) | n/a | Revised Total Coliform Rule | resolved 2018-02-20 |
Monitoring and reporting violations (150)
A required sample or report was late or missing. These do not mean a contaminant was found, but a system that skips monitoring has gaps in its record.
| Year | Rule | Count | Detail |
|---|---|---|---|
| 2024 | Lead and Copper Rule Revisions | 1 | |
| 2024 | Ground Water Rule | 2 (2 open) | Monitoring, routine major (TCR) · E. coli |
| 2023 | Synthetic Organic Chemicals | 116 | Routine monitoring, major · 1,2-Dibromo-3-chloropropane, Atrazine |
| 2021 | Volatile Organic Chemicals | 21 | Routine monitoring, major · Benzene, Tetrachloroethylene, Trichloroethylene |
| 2021 | Synthetic Organic Chemicals | 2 | Routine monitoring, major |
| 2021 | Radionuclides | 4 | Routine monitoring, major · Gross Alpha, Radium 226 + 228, Uranium |
| 2021 | Nitrates | 1 | Routine monitoring, major · Nitrate (as N) |
| 2020 | Nitrates | 1 | Routine monitoring, major · Nitrate (as N) |
| 2018 | Ground Water Rule | 1 | Monitoring, routine minor · E. coli |
| 2013 | Public Notification Rule | 1 (1 open) | Public notice rule linked to violation |
Lead and copper at the tap90th percentile of sampled homes against the action level
90th percentile of samples taken at customer taps. Results depend on the home's plumbing. Results are from sampled homes in this system, not from your tap. Home plumbing can add lead and copper. First-draw samples run higher than flushed ones.
90th percentile of samples taken at customer taps. Results depend on the home's plumbing. Results are from sampled homes in this system, not from your tap. Home plumbing can add lead and copper. First-draw samples run higher than flushed ones.
Where the water comes from9 active wells
9 active wells, and 9 treatment points on record (SDWIS counts each chlorination or filtration point as a treatment plant).
WELL #1: Susceptibility: ioc moderate, voc moderate, soc high (auto), microbial moderate.
Source water assessment susceptibility: final map[IOC:Moderate Microbials:Moderate SOC:Auto High VOC:Moderate]; hydrologic sensitivity H; pci land use map[IOC:M Microbials:M SOC:M VOC:M]; system construction M;
Source names (9)
WELL #1, WELL #11, WELL #12, WELL #13, WELL #14, WELL #15, WELL #16, WELL #6, WELL #9
Every match, by categorytop three per category
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Drinking water
Under sink, pitcher, or faucet. Treats the water you drink and cook with.
Brondell Circle RC100 Reverse Osmosis System
Certified for arsenic, fluoride, and total trihalomethanes (NSF/ANSI 58, pentavalent, NSF/ANSI 53).
Plumber recommended if you are not comfortable with a drain saddle and a tank. Not a whole-house solution.
Aquasana OptimH2O Reverse Osmosis + Claryum
Certified for arsenic, nitrate, and fluoride (NSF/ANSI 58, pentavalent); manufacturer-reported for radium 226 + 228.
Plumber recommended if you are not comfortable with a drain saddle and a tank. Not a whole-house solution.
Clearly Filtered Water Pitcher
Certified for total trihalomethanes and haloacetic acids (NSF/ANSI 53); manufacturer-reported for arsenic, nitrate, and fluoride.
DIY. No plumbing.
Whole house
Installed where water enters the house. For fixtures, laundry and showers.
Nothing in this water calls for whole-house treatment. A drinking-water filter covers the exposure that matters. Whole-house units here are optional, mainly for taste and chlorine.
Crystal Quest Ultimate Whole House Arsenic Removal Filter (Triple Cartridge, 4-6 GPM)
Manufacturer-reported reduction for arsenic. Not NSF-certified for arsenic.
Plumber recommended if you are not comfortable with this install.
Aquasana Rhino EQ-1000 Whole House Filter (1,000,000 gallons)
Manufacturer-reported reduction for total trihalomethanes. Does not address arsenic.
Plumber recommended if you are not comfortable with this install.
Sprite High Output 2 Universal Shower Filter with 3-Setting Shower Head (HO2-WH-M)
Does not address arsenic.
DIY. No plumbing.
Softener or conditioner
Worth it at 7 grains per gallon or more.
Whirlpool WHES40E 40,000 Grain Water Softener
Certified for radium 226 + 228 (NSF/ANSI 44). Does not address arsenic.
DIY if you are comfortable with this install.
Aquasure Serene Lite 650K Salt-Free Water Conditioner with Triple Purpose Pre-Filter
Does not address arsenic.
Plumber recommended if you are not comfortable with this install.
Whirlpool WHES30E 30,000 Grain Water Softener
Does not address arsenic.
DIY if you are comfortable with this install.
Questions about City of Mountain Home
Is City of Mountain Home tap water safe to drink?
City of Mountain Home met every federal limit in the last 36 months, with no open health-based violation. 1 contaminant was at half the limit or higher: Arsenic. The results table shows each value against its limit. Results reflect the system's sampling points, not the plumbing in any one home.
Is City of Mountain Home water hard?
Hardness has not been reported for City of Mountain Home in a reviewed Consumer Confidence Report yet. The softener sizing widget uses a labelled county default until a report is reviewed.
Is City of Mountain Home water fluoridated?
Fluoride was measured at up to 0.38 mg/L, below the 0.7 mg/L level used for community fluoridation, so it is naturally occurring rather than added. The federal limit (MCL) is 4 mg/L.
Where does City of Mountain Home water come from?
City of Mountain Home draws from 9 active wells with 9 treatment plants on record. Source and treatment details are listed above.
What filter fits City of Mountain Home water?
For drinking water the matching engine ranks Brondell Circle RC100 Reverse Osmosis System first for this profile, based on certified reduction claims for the contaminants flagged above. See the filters section for the reasoning and alternatives.
Who to call
- System contact: SONNENTAG, DAVID, 208-587-2108
- DEQ Boise Regional Office, 1445 N Orchard St, Boise ID 83706, (208) 373-0550
- Central District Health (well testing, septic, local health questions)
Sources
Sample results as of 2026-08-26; inventory and violations from EPA SDWIS; page built 2026-09-14. 336 individual results reviewed.
More: Mountain Home water, Elmore County, Arsenic
Numbers are the system's samples at its taps and wells, not yours. Lead and copper are 90th percentiles from sampled homes. Well pages are nearby-sample estimates. Health text restates EPA and DEQ. Methodology.