Sundance Improvement Association
What EPA’s and Washington’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.
- Serves
- 100 people
- Connections
- 26
- Water source
- Groundwater
- Based in
- Kennewick, WA
- County
- Benton
- Owner
- Private
The ZIP code it serves
The short answer
1 result is above EPA’s legal limit, and 2 more are above the health goal. The worst: Nitrate, above the legal limit. 14 health-based violations since 2016.
What handles itWhat was found
Lead and copper: EPA SDWIS monitoring periods ending 1998 to 2023.
Nitrate, arsenic, total trihalomethanes (TTHM) and haloacetic acids (HAA5): Washington’s own results, samples taken from Feb. 4, 2020 to Sept. 8, 2026, with EPA’s 2012 to 2019 file for earlier years.
Fluoride and chromium (total): EPA’s compliance monitoring file, samples taken from May 7, 2019 to May 7, 2019. Newer results are in the utility’s annual water quality report.
Above the legal limit1
Nitrate
Comes from the source
12.1ppm
Highest sample; found in 28 of 28
2026 average: 7.6 ppm
From 2020 to 2026, five samples were above EPA’s legal limit of 10 ppm, the highest 12.1 ppm in 2024. Five have no follow-up sample on file within 30 days. In 2026, the latest year on file, its four samples averaged 7.6 ppm. EPA recorded violations for nitrate at this utility in 2020, 2021, 2023, 2024, 2025 and 2026. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 12.9 ppm, in 2019, and EPA recorded violations in 2017, 2018 and 2019.
What handles it
- NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
- NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
Above the health goal2
Arsenic
Comes from the source
8.4ppb
Highest yearly average, 2022 to 2025
2025, one sample: 8.3 ppb
Averaged by year, the highest was 8.4 ppb, in 2022: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2025, the latest year on file, its one sample was 8.3 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 7.5 ppb, in 2019.
What handles it
- NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
- NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
Lead
Comes from pipes, often your own
4.3ppb
90th percentile, 2023
In the latest period, 9 in 10 homes sampled were at or below 4.3 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.
What handles it
- NSF/ANSI 53 look for “Lead Reduction”
- NSF/ANSI 58 look for “Lead Reduction”
Below EPA’s limits3
Total trihalomethanes (TTHM)
Forms or is added in treatment
16ppb
Highest yearly average, 2021 to 2024
2024, one sample: 4.5 ppb
Averaged by year, the highest was 16 ppb, in 2021, below EPA’s legal limit of 80 ppb. In 2024, the latest year on file, its one sample was 4.5 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 32.3 ppb, in 2015.
What handles it
- NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
- NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
Haloacetic acids (HAA5)
Forms or is added in treatment
9.1ppb
Highest yearly average, 2021 to 2024
2024, one sample: 7.8 ppb
Averaged by year, the highest was 9.1 ppb, in 2021, below EPA’s legal limit of 60 ppb. In 2024, the latest year on file, its one sample was 7.8 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 19.4 ppb, in 2015.
What handles it
No certification claim covers this compound yet.
Fluoride
Forms or is added in treatment
0.34ppm
Highest yearly average, 2019
Averaged by year, the highest was 0.34 ppm, in 2019, below EPA’s legal limit of 4.0 ppm. That is the only year on file.
What handles it
- NSF/ANSI 58 look for “Fluoride Reduction”
- NSF/ANSI 53 look for “Fluoride”
One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
- Chromium (total)
What handles it
A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”
- NSF/ANSI 53
Claims: Nitrate/Nitrite (30 ppm challenge), Arsenic (Pentavalent)<=50 ppb Reduction, Lead Reduction
For: Nitrate, Arsenic, Lead
Other certifiers’ wording: Arsenic (III) (50 ppb influent level)
- NSF/ANSI 58
Claims: Nitrate/Nitrite Reduction, Arsenic (Pentavalent)<=50 ppb Reduction, Lead Reduction
For: Nitrate, Arsenic, Lead
Other certifiers’ wording: Nitrate; Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)
At the tap, or for the whole house?
Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. How whole-house systems compare.
Filters with those claims on a certifier’s listing
Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money
Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Nitrate, Arsenic, Lead
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Nitrate, Arsenic, Lead
Culligan 10-Cup Pitcher with ZeroWater Technology (ZEROP10)
Pitcher
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 401checked Oct. 9, 2026
Certified for: Nitrate, Lead
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic, Lead
Violations since 2016
| Contaminant or rule | Type | Period | Measured | Status |
|---|---|---|---|---|
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | April 1, 2026 to June 30, 2026 | 11.7 MG/L | Archived |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2025 to Dec. 31, 2025 | 10.4 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2025 to Dec. 31, 2025 | 10.5 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2024 to Dec. 31, 2024 | 12.1 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2024 to Dec. 31, 2024 | 10.2 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2023 to Dec. 31, 2023 | 10.1 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2021 to Dec. 31, 2021 | 11.6 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | July 1, 2020 to Sept. 30, 2020 | 10.7 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | July 1, 2019 to Sept. 30, 2019 | 12.9 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2019 to Dec. 31, 2019 | 12.2 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2018 to Dec. 31, 2018 | 12.7 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2018 to Dec. 31, 2018 | 10.4 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2017 to Dec. 31, 2017 | 11.7 MG/L | Resolved |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2017 to Dec. 31, 2017 | 12.8 MG/L | Resolved |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 4 monitoring or reporting violations not shown. | ||||
What this report can’t tell you
Everything else. Nitrate, arsenic, total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are Washington’s own from 2020 on, with EPA’s national file for 2012 to 2019. Fluoride and chromium (total) come from EPA’s file alone, which ends in 2019. Sundance Improvement Association’s own annual report, which it must send you every year, has newer results for those and the contaminants this page does not show.
Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.
What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.
Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; Washington’s results run from Feb. 4, 2020 to Sept. 8, 2026; EPA’s compliance samples are from May 7, 2019 to May 7, 2019.
Testing your own tap
The 3 labs Washington certifies closest to the area Sundance Improvement Association serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Benton-Franklin Health District Lab
Kennewick, WA · about 11 miles
Certified for bacteria, nitrate, minerals and other inorganics
Energy NW Environmental (PPL) Lab
Richland, WA · about 16 miles
Certified for bacteria
Energy Northwest Environmental Services Lab
Richland, WA · about 20 miles
Certified for nitrate, lead and copper, metals, minerals and other inorganics
Sources
- EPA UCMR 5 occurrence data, file of Oct. 15, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q3
- Washington State Department of Health, Office of Drinking Water, results from Jan. 1, 2020 to Sept. 29, 2026, read Oct. 8, 2026
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- Certified labs: Washington State Department of Ecology, Lab Accreditation Program, environmental laboratories accredited for drinking water analyses, read Oct. 10, 2026; distances from the Census 2020 ZIP code tabulation area gazetteer
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID WA5385209. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Read up on the 3 results above a lineWhat each one does to health, where it comes from, and the certification claim that addresses it.Start with Nitrate
- Get the utility’s own reportSundance Improvement Association must send you a water quality report every year. It covers contaminants this page does not show, and has newer results than EPA’s national file for the ones here that come from it.How to read it
- Test your own tap for leadYour service line, solder and fixtures decide the lead at your faucet, not the utility’s average.Lead in your water: what to do
- Compare certified filtersWhat the filters certified for these results cost over five years, cartridges included.Compare five-year costs