Most property owners never think about it — until something goes wrong. Here's what backflow is, why it's a public health risk, which device protects your property, and what Iowa law requires.
Most people never think about it — until something goes wrong. Here's what backflow is, why it's a public health risk, and why your property is required to have protection against it.
Your water supply is designed to flow one way: from the city main into your building. Backflow is when that direction reverses — and contaminated water from your property gets pushed or pulled back into the public drinking water supply.
It can happen in seconds. A water main break, a sudden drop in pressure, or a firefighting draw can create the conditions for backflow — and once contaminated water enters the public main, it can affect an entire neighborhood.
When pressure drops, contaminated water can reverse into the city main
Common sources of cross-connection hazards
A cross-connection is any physical link between your potable (drinking) water supply and a source of contamination. They exist in almost every commercial building.
Irrigation systems, fire suppression lines, boilers, chemical mixing stations, commercial kitchens — all of these create potential cross-connections that, under the wrong pressure conditions, can introduce hazardous materials into the drinking water supply.
A backflow preventer is a mechanical device installed on your water line that uses a series of check valves to ensure water can only flow one direction — into your building, never back out.
State and local regulations require most commercial properties to have certified backflow preventers installed — and critically, tested annually by a licensed tester to verify they're working. A device that looks fine may be failing internally.
Iowa Requirement
Iowa Administrative Code 567 Ch. 43 requires backflow prevention on all commercial water service connections. Iowa American Water enforces annual third-party testing and BSI Online filing for all accounts in its service area. Non-compliance can result in service interruption.
Reduced Pressure Zone (RP) — the most common assembly type for high-hazard accounts
Five assembly types are used in commercial backflow prevention. The one installed at your property depends on your hazard level and application.
| Assembly | Hazard Level | How It Works | Typical Use | Fail Visible? |
|---|---|---|---|---|
| RP Reduced Pressure Zone |
High | 2 check valves + relief valve that discharges if either check fails | Domestic service, irrigation, kitchens, boilers, healthcare | ✅ |
| DC Double Check Valve |
Low | 2 check valves, no relief valve — closed system, failure is invisible | Fire suppression (no chemicals), low-hazard commercial | ❌ |
| PVB Pressure Vacuum Breaker |
Low–High | Check valve + air inlet; prevents backsiphonage only, must be above highest outlet | Lawn irrigation — many utilities now require RP on replacement | ⚠️ |
| DCDA Double Check Detector |
Low | DC + bypass meter that flags any flow under 3 GPM (leaks or theft) | Main fire service lines — low-hazard systems | ❌ |
| RPDA RP Detector Assembly |
High | RP + bypass meter — highest protection for fire systems with chemicals | Fire suppression with antifreeze, foam, or chemical injection | ✅ |
Not sure which type is at your property? We identify and verify your assembly during every test and free compliance audit.
Any substance that can make you sick — chemicals, pathogens, medical fluids, fertilizers, fire suppressants with additives.
Substances that affect taste or odor but not health — beverage equipment, standard office water service, fire systems without additives.
The state rule that requires backflow prevention on all commercial water service connections in Iowa. If you have a commercial water meter, this applies to you.
Iowa American Water operates a Cross-Connection Control program requiring annual testing by a licensed tester and results filed through BSI Online. Notices of non-compliance are issued when deadlines are missed.
Most commercial, industrial, and institutional accounts — restaurants, offices, schools, medical facilities, irrigation systems, and more. Residential accounts with irrigation or other hazards may also be required.
That's the most common question we get. A free compliance audit takes 15 minutes and gives you a straight answer — no jargon, no obligation.
Get a Free Audit →Does your property have a backflow preventer?
If you're not sure — or haven't had it tested this year — we can help. A free compliance audit takes 15 minutes and tells you exactly where you stand.