St. Peters
MO

Is St. Peters, MO Tap Water Safe to Drink?

St. Peters tap water meets federal Safe Drinking Water Act standards but 1 of 1 ZIP code show detections above EPA health guidelines, primarily for lithium. A certified filter is recommended for households that want an additional layer of protection.

2Water systems
1ZIP codes
100%ZIPs above EPA guideline
Metro areaSt. Louis, MO-IL
Latest data2025-09-15

Where Does St. Peters Get Its Water?

Water in St. Peters, MO is provided by 2 public water systems: OFALLON PWS and ST PETERS PWS.

How Is St. Peters Tap Water Treated?

Treated water is disinfected using free chlorine and calcium hypochlorite and chloramines. Treatment includes conventional treatment (coagulation, flocculation, and filtration), direct filtration, ion exchange, in-line filtration, membrane filtration and slow sand filtration.

What's in St. Peters Tap Water?

The following contaminants were detected most frequently in St. Peters public water systems. 1 of 1 ZIP codes showed detections above EPA health guidelines.

ContaminantPeak detectedEPA guidelineZIPs detectedStatus
lithium 36.4 µg/L 10 µg/L 1 ZIP Above guideline
PFTrDA 0.007 µg/L — 0 ZIPs Within guideline
11Cl-PF3OUdS 0.005 µg/L — 0 ZIPs Within guideline
HFPO-DA 0.005 µg/L — 0 ZIPs Within guideline
8:2 FTS 0.005 µg/L — 0 ZIPs Within guideline

Health Risk Profile for St. Peters

Based on EPA monitoring data, 1 of 1 ZIP codes in St. Peters have recorded detections above EPA health guidelines. Sensitive populations such as infants, pregnant individuals, and those with weakened immune systems may benefit from an additional layer of protection such as a certified point-of-use filter.

Best Broad-Spectrum Filters for This Water Profile

This city profile includes PFAS detections, chlorine disinfection, and other dissolved contaminants. Reverse osmosis (RO) systems certified under NSF/ANSI 58 provide broad reduction coverage; for PFAS specifically, confirm NSF/ANSI P473 or equivalent PFAS reduction certification.

Waterdrop G3P600 Reverse Osmosis System
Under-sink RO system

8-stage tankless RO system certified to NSF/ANSI 58, reduces 1,000+ contaminants including PFAS, lead, arsenic, fluoride, and nitrates.

See recommendations matched to your exact address: choose your ZIP code below.

Frequently Asked Questions about St. Peters Tap Water

Is St. Peters tap water safe to drink?

St. Peters tap water meets Safe Drinking Water Act requirements but 1 of 1 ZIP codes show contaminant levels above EPA health-based guidelines. A certified point-of-use filter adds an extra layer of protection.

What contaminants are in St. Peters tap water?

The most commonly detected contaminants in St. Peters water systems include: lithium, PFTrDA, 11Cl-PF3OUdS. See the ZIP-level reports for exact measurements and EPA guideline comparisons.

Where does St. Peters get its drinking water?

St. Peters receives water from 2 public water systems, including OFALLON PWS.

Do I need a water filter in St. Peters?

If your ZIP code is among those with detections above EPA health guidelines, choose a filter certified for the specific contaminants shown in your ZIP report. Reverse osmosis is generally the broadest option for PFAS, lithium, and many other dissolved contaminants.

How often is St. Peters tap water tested?

Public water systems in St. Peters are required by the EPA to test for regulated contaminants on schedules ranging from daily (for microbials and disinfectants) to annual or triennial (for many chemical contaminants). Results are published in annual Consumer Confidence Reports (CCRs). The data on this page reflects the most recent available EPA monitoring results, with the latest sample date of 2025-09-15.

Tap water reports by ZIP in St. Peters

Water utilities serving St. Peters, MO

Service area boundaries are approximate and based on state filings or modeled estimates. Contact your utility to confirm exact service at a specific address.

Modeled boundaries are shown with a dashed outline.

Also covers / overlaps with