Most utilities unknowingly operate in the “backflow gap”—the gap between the number of test records and the actual number of backflow prevention assemblies connected to the distribution system. Irrigation systems often make that gap bigger.
Utilities need to take a broader approach to protecting community drinking water from the hazards that could be introduced via backflow from irrigation systems. Limiting backflow prevention and cross-connection control efforts to annual testing leaves too much risk on the table. You need to know what records you have and where gaps exist, where irrigation systems are, what risks they present, and how they’re protected.
Compliance Insights: Building a Defensible Cross-Connection Control Program
Irrigation Systems
Why High Hazard?
Irrigation systems, in most state plumbing codes, are considered high-hazard connections. The reason is threefold:
- Exposure to contaminants: soil, standing water, fertilizer, pesticides
- Frequent modifications and alterations: seasonal service, repairs, additions
- Inherent hydraulic problems: backpressure, backsiphonage
You might first think of irrigation systems at residential service connections, but public water systems must account for their use in commercial, municipal, institutional, and agricultural contexts, too. Often, these systems operate in high complexity scenarios or with higher output, introducing additional risks. Large corporate or school campuses, mixed uses, multiple zones, booster pumps, master valves, and remote controls can all increase the associated risk.
Many utilities operate with a sense of uncertainty when it comes to irrigation. Missing test records, repeated and undocumented modifications, failed backflow prevention assembly tests, and changes in ownership all have the capacity to create backflow risks.
So, what do you specifically need to look for as part of your cross-connection control program?
Chemical Injections
- Injection substance
- Timing
- Tanks
- Tubing
- Injectors, pumps, and valves
- Chemical labels
- Nutrient feed equipment
Alternative Water Sources
- Sources like private wells, ponds, lakes, cisterns, rainwater, and reclaimed water
- Cross-ties
- Common manifolds
- Bypasses
- Shared valve boxes
Booster Pumps
- Pump location
- Controls
- Pressure Settings
- Bypass piping
- Position in relation to backflow preventer
Modifications
- New zones
- Moved devices
- Winterization ports
- Pump additions
- Bypasses
- Chemical feed
- Source changes
Verifiable Evidence
You need verifiable evidence to ensure that protection decisions align with state plumbing code requirements. The only way to get that evidence is to look for it on-site. Start with an inventory of irrigation systems within your utility. Identify every account, separate them out by use, and record whether they are active, seasonal, or abandoned. Don’t forget to check on service connections with uncertain irrigation connections.
Field surveys allow you to get more information than what you can get from backflow test records. A backflow test only tells you if the assembly works at the moment of testing. It can’t tell you whether the assembly is installed properly, installed in the right location, or even the correct assembly for the use case. Surveys help you a) identify backflow preventers (and where additional protection is needed), and b) identify any changes to the system since your last survey.
On-site, gather information about the backflow assembly, including:
- Assembly type
- Manufacturer
- Model
- Size
- Serial number
- Tag
Also, make sure to get additional system condition data such as:
- Installation details
- Valves
- Drains
- Bypasses
- Pumps
- Sources
- Chemicals
- Observed defects
Field surveys should identify system changes and intent to ensure existing protection still matches the use. And, if it doesn’t, corrective actions need to be taken. Ask questions specific to irrigation systems like:
- What water sources can and do supply the irrigation system?
- Are fertilizers, pesticides, treatments, or other chemicals ever injected?
- Is there a booster pump, storage tank, or elevation change?
- Has anything been added, removed, repaired, or winterized since the last survey?
- Who maintains the system? How do they communicate system changes to the utility?
Protecting your system from backflow, including from irrigation systems, takes a significant amount of time, labor, and ongoing management. It requires recurring on-site surveys that ask the right questions, document findings, and enforce compliance every time. Counting irrigation systems as high hazard is the first step in addressing the risks they pose to your utility and your community’s drinking water.
Ready to learn more about how HydroCorp can support your cross-connection control efforts?
