No plumbing code sets one interval for apartments, and the code puts maintenance on the owner. EPA's commercial guidance suggests daily walk-throughs, monthly meter and bill reviews, and a full water assessment every four years. Layer annual valve, pressure and backflow checks on top, and tighten the schedule for older buildings.
What does the code actually require?
The plumbing code makes maintenance the owner's job and does not name an interval. Section 102.3 of the 2024 International Plumbing Code, which Phoenix adopts without amending that section, says plumbing systems "shall be maintained in proper operating condition in accordance with the original design in a safe and sanitary condition." It adds that "The owner or the owner's authorized agent shall be responsible for maintenance of plumbing systems." Other rules attach to specific equipment, such as annual testing for backflow assemblies in many Valley cities, and those dates are fixed by the city rather than by you.
In Arizona's apartment law, the landlord must keep plumbing working too: A.R.S. 33-1324(A)(4) covers plumbing in dwelling units. That makes a documented routine your best evidence of reasonable care. Our page on plumbing documentation for commercial insurance covers record keeping.
What cadence does EPA suggest?
EPA's WaterSense program publishes leak-detection practices for commercial and institutional buildings, and most of it fits an apartment property. Its leak detection guidance says: "Reading water meters regularly, installing leak detection and flow monitoring devices, and conducting visual and auditory inspections are important best practices to detect leaks." It then gives specific intervals:
- Daily: "Perform daily tours of the building wherever water use occurs," including restrooms, kitchens, irrigation systems, and mechanical spaces. EPA adds that building maintenance staff "can usually complete these walkthroughs without much extra effort."
- Monthly: where advanced metering data is not available, EPA says to read the meters and the bills every month, and to compare each month to the previous month and the same month a year earlier.
- Every four years: "Perform a water assessment of the facility once every four years," with the note that if more than 10 percent of water use cannot be accounted for, the facility may have leaks and further investigation is warranted.
Sensors help between visits. EPA describes leak sensors as small devices placed in areas prone to leaks, such as under sinks and near water heaters, toilets, dishwashers and ice machines.
What schedule works for an apartment building?
Use the EPA cadence as the spine and add the items apartments have in particular. The first rows below come from the sources. The rest are suggestions to adapt to your building, not code requirements.
| How often | What to check | Basis |
|---|---|---|
| Daily or each site visit | Common restrooms, laundry rooms, pool equipment, irrigation, mechanical rooms, wet spots | EPA daily tours |
| Monthly | Master meter and bill against the prior month and the same month last year | EPA monthly review |
| At each unit turnover | Toilets, faucets, showerheads, supply stops, under-sink and water heater areas | Suggested |
| Every year | Exercise building and unit shutoff valves; pressure at the building; water heater and relief valve; backflow assembly test where the city requires it | Suggested; backflow dates set by the city |
| Every few years | Sewer camera inspection of the building drain and sewer, more often for older pipe | Suggested |
| Every four years | Whole-property water assessment | EPA |
Two of those rows deserve a note. EPA's Fix a Leak Week page says a toilet's flapper "should be checked periodically and replaced at least every five years to ensure a good seal and avoid leaks," which is a natural fit for a turnover check. And Phoenix says "Water pressure greater than 80 psi requires action by the home or business owner as it can damage your water pipes and appliances," and that customers must install a pressure regulator on their side of the meter. A yearly pressure check tells you whether yours is still doing its job.
When should you inspect more often?
Tighten the schedule when the building gives you a reason to:
- Age. Older pipe fails more often. See how long cast iron drain pipe lasts.
- History. A building with repeat stoppages or a prior leak deserves a shorter loop on that line, much like the drain cleaning interval depends on the building.
- Water damage claims. Insurers ask what you did to prevent the loss. Dated inspection records help.
- Monsoon and summer heat. Roof drains, irrigation, and cooling use water in ways you will see on the meter.
- Unusual bills. A jump on the meter should trigger a check right away. See finding which unit is driving the bill.
Who should do which inspections?
Staff can do the daily tours, the meter reads, and the turnover checks with a short checklist. A licensed plumber is the right person for the annual valve and heater work, pressure checks, backflow testing, camera work, and anything that needs a permit. Bring one in earlier if a tenant reports recurring low pressure, discolored water, or slow drains in several units, because those point at shared lines.
HQ inspects and services plumbing in multifamily buildings and gives an upfront price and a free estimate for the work, with licensed and insured crews. This page explains general guidance and is not legal advice.