Marion County, Indiana has about 981,628 residents (Census 2024 estimate) and 3 community water systems in EPA records. The largest local system is Citizens Water - Indianapolis, serving about 880,345 people from surface water.
! 1 of 3 largest systems with health-based violationsPFAS detected at 2 of 3 sampled systemsHardness 18.5 gpg (high confidence)
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
How hard is Marion County water?
Citizens Water - IndianapolisMeasured (utility report, 2025) · High confidence
18.5 gpg(317 mg/L), very hard · range 148–460 mg/L
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
Softener size at 18.5 gpg
For a 3-person home using 57 gallons per person per day and regenerating weekly, you'd remove about 22,145 grains between regenerations. Suggested size: 24,000 grain.
Estimate only. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
The 3 biggest of 3 community water systems on EPA records for this county. Service areas don't follow county lines; your water bill names your provider.
Citizens Water - Indianapolis
IN5249004 · serves about 880,345 people · Surface water
✓ No health-based violations✓ Lead below action levelPFAS detected (4 types)
Lead 90th percentile: 3.4 ppb (period starting 2026-01-01). Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
PFPeA: highest sample 7.6 ppt (11 of 26 samples); no federal limit
PFBA: highest sample 5.7 ppt (2 of 26 samples); no federal limit
PFHxA: highest sample 5.1 ppt (9 of 26 samples); no federal limit
PFBS: highest sample 4 ppt (3 of 26 samples); no individual limit; counted in EPA's PFAS mixture (hazard index) limit
IN5249008 · serves about 10,578 people · Surface water
✓ No health-based violations✓ Lead below detectionPFAS detected (3 types)
Lead 90th percentile: <DL (below the lab detection/reporting limit; reported as 0) (period starting 2021-01-01) Older result. Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
PFBA: highest sample 18 ppt (3 of 6 samples); no federal limit
PFPeA: highest sample 5.4 ppt (5 of 6 samples); no federal limit
PFHxA: highest sample 4 ppt (2 of 6 samples); no federal limit
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
A PFAS detection is not a violation. Federal limits (4 ppt for PFOA and PFOS) apply to running annual averages, with compliance required by 2029. In May 2026 EPA proposed extending the PFOA/PFOS deadline to 2031 and removing other PFAS limits; not final as of 2026-10-21.
Test your own tap
These are public records for whole systems. Your home's pipes, fixtures and any private well can change what you drink. A certified lab test or a hardness test strip gives you your own numbers. Then use our PFAS and lead filter selector to see which certifications to look for.
Common questions about Marion County water
Is tap water in Marion County safe to drink?
1 of the 3 largest systems here have at least one health-based violation in EPA records since October 2021 (see each system below for status). Citizens Water - Indianapolis's most recent lead 90th percentile was 3.4 ppb (2026), below the 15 ppb action level. Public records can't guarantee what comes out of your tap, especially with older plumbing, so a home test is the surest check.
How hard is the water in Marion County?
Citizens Water - Indianapolis reports about 18.5 grains per gallon (317 mg/L), which is very hard. For a 3-person home at 18.5 gpg, our softener calculator suggests a 24,000 grain unit as a starting point.
Is there PFAS in Marion County water?
2 of the 3 sampled systems listed here detected at least one PFAS in EPA's UCMR 5 testing. A detection isn't a violation: federal PFAS limits apply to running annual averages starting in 2029.
Which water system serves my address in Marion County?
Most homes are served by Citizens Water - Indianapolis or one of the other systems listed on this page, but service areas don't follow county lines. Your water bill names your provider, and its annual Consumer Confidence Report has the full test results.
Data as of October 21, 2026. Figures are copied from public records and combined with our own calculations; they can be out of date or wrong. Tapped Out isn't affiliated with any utility or the EPA. Written and reviewed by the Tapped Out team. How we calculate · All sources.