Guide · for park owners and managers
Running a mobile home park water system
Short answer
A park that supplies its own water to 15 or more lots with year-round residents, or to 25 or more year-round residents, is a community water system. That means a certified operator, monthly coliform samples (for most small ground water parks), chlorine residual readings if you chlorinate, a Consumer Confidence Report by July 1 each year, a state sanitary survey at least every three years, and records of all of it.
Is your park a public water system?
Under federal rules, a system with at least 15 service connections, or that regularly serves an average of 25 people a day on 60 or more days a year, is a public water system. It's a community system when 15 connections are used by year-round residents or it serves 25 year-round residents (40 CFR 141.2). Most parks with their own well meet that easily. Run your numbers through the public water system checker.
If the park buys all its water from a city or district, doesn't treat it and doesn't sell it, the federal regulations may not apply (40 CFR 141.3), but whether billing residents counts as selling is your state's call.
Where parks go wrong
An Associated Press review of EPA data in 2025 found that nearly 70% of mobile home parks running their own water systems had violated safe drinking water rules in the previous five years, and more than half had failed to perform a required test for at least one contaminant or to properly report the results (AP via CPR News). Most of that is paperwork and scheduling, not a treatment failure: a sample not taken, a report not filed, a reading not recorded. Those are the problems a steady log and a calendar prevent.
Owner and operator
The owner is responsible for the system. EPA's operator certification guidelines require owners of community and non-transient non-community systems to put the system under the responsible charge of a certified operator, and EPA's guidance says a mobile home park that meets the definition needs one (EPA 816-R-00-022). Many parks contract a licensed operator for oversight and have their own maintenance staff do the daily round. That works, as long as the daily readings are recorded properly and the operator actually reviews them.
The compliance calendar
A typical small ground water park that chlorinates. Your state's schedule is what counts; the examples show the range.
| When | What | Basis |
|---|---|---|
| Daily or weekly | Chlorine residual at your state's frequency; source meter, pressure and chlorinator on the daily round | State rules, e.g. weekly in Texas, daily in Ohio |
| Monthly | Coliform sample (ground water systems of 1,000 or fewer), with a chlorine residual measured at the same time and place | 141.855, 141.132 |
| Monthly | Operating report to the state, often by the 10th | State rules; see monthly operating reports |
| Quarterly | Chlorine running-annual-average report, within 10 days after the quarter (Texas: the DLQOR) | 141.133–141.134, TCEQ |
| Every July 1 | Consumer Confidence Report to residents, covering the previous year | 141.152 |
| Every 3 years | State sanitary survey (every 5 for systems that qualify) | 142.16(o) |
The sanitary survey reviews your source, treatment, distribution, storage, pumps, monitoring and reporting, management and operator compliance (40 CFR 141.401). An organized log is the easiest part of it to get right.
Records to keep
Coliform results for 5 years, chemical results and sanitary surveys for 10, and your state's period for daily logs and residual readings (often 3 years). The full list, with state examples, is in how long to keep water system records. Keep them on site or nearby, and able to be shown to an inspector.
Water use and leaks
Old service lines are a park's biggest hidden cost. Read the source meter every day and turn the readings into gallons per day with the meter usage calculator. Give it your lot count to see use per connection. A sustained jump that occupancy and weather don't explain is usually a leak. If lots are metered, the water loss calculator shows how much never reaches a meter. If the pump runs longer every month for the same water, check the well pump GPM.
Keeping the log when you're not on site
- Write the round down once, exactly: which tap, which meters, what counts as normal.
- Give whoever does it a sheet or an app with those readings already laid out.
- Insist on initials and the time on every entry.
- Review the log weekly, not at month end, so a missed day or a low residual is caught while it matters.
Printable options: the daily water system log sheet and the chlorine residual log sheet.
Questions
Does my mobile home park need a certified operator?
If it's a community water system, almost certainly. EPA's operator certification guidelines say owners of community and non-transient non-community systems must place the system under the responsible charge of a certified operator, and its guidance addresses mobile home parks directly: if the park meets the definition, a certified operator is required. Your state sets the license class.
My park buys water from the city. Am I a public water system?
Possibly not under federal rules. A system that only distributes and stores water bought from a regulated public system, doesn't treat it, doesn't sell it and isn't an interstate carrier is exempt from the federal regulations (40 CFR 141.3). Whether billing residents for water counts as selling it is up to your state, so ask.
How often do I have to test chlorine?
Your state decides. Examples: Texas small ground water systems test the distribution system at least weekly and with each coliform sample; Ohio tests daily; Pennsylvania takes a daily entry-point sample and weekly distribution samples. Community systems that chlorinate must at least measure the residual with every coliform sample under federal rules.
What's a Consumer Confidence Report?
An annual water quality report every community water system delivers to its customers, by July 1 each year, covering the previous calendar year's results. Your state program usually provides a template.
Sources
- 40 CFR 141.2 — Definitions (public, community, non-transient and transient water systems)
- 40 CFR 141.3 — Coverage (systems that only distribute purchased water)
- Associated Press via CPR News — Mobile home park drinking water violations (July 26, 2025)
- EPA — About operator certification
- EPA 816-R-00-022 — Operator certification guidelines: implementation guidance
- 40 CFR 141.855 — Coliform monitoring for community ground water systems ≤1,000 people
- 40 CFR 141.132 — Monitoring requirements (residual with total coliform samples)
- 40 CFR 141.133 — Compliance requirements (running annual average)
- 40 CFR 141.152 — Consumer Confidence Report deadlines
- 40 CFR 141.401 — Sanitary surveys for ground water systems
- 40 CFR 142.16(o) — Sanitary survey frequency for ground water systems
- TCEQ — Disinfection Level Quarterly Operating Report (DLQOR)
Last reviewed September 28, 2026. Rules change and states add their own; confirm with your state drinking water program.