There can be many reasons why your secondary water system would experience drops in pressure. When you do experience a noticeable drop in pressure the first item to always check is your filter. Debris in the secondary water such as sand, small cobbles, weeds, and grass can accumulate in your filter and prevent the water from flowing through it freely. As a result, you can experience a large pressure loss or drop through the filter that will result in low pressures on your pressurized irrigation system.
Your filter is typically located just downstream of your main shutoff valve usually in one of the front corners of your lot. If your system was installed prior to 1990, your main shutoff valve may be located in one of the back corners of your lot. The filter, depending on the type, will usually have a blowoff valve that can be opened to flush the filter of debris. You can try opening this valve to flush the filter of debris. However, it is usually better to remove the filter from the casing and clean/rinse it thoroughly with clean water. This method will do a much better job of cleaning your filter. Even if you are not experiencing pressure problems, you should clean your filter on a regular basis throughout the irrigation season.
If your filter is clean and you are still experiencing pressure problems, the next item to check is your irrigation system for leaks. A leak in your irrigation system will prevent your system from fully pressurizing and result in low pressure. Conduct a thorough inspection of your property for any ponding water or wet areas in your lawn. As you are conducting this inspection, also check your spray heads to ensure that they are not plugged with debris. Plugged spray heads are also a major culprit of pressure problems.
If you have inspected your system and think that you do not have any leaks, then the next item to check is your main shut off valve to ensure it is fully open. If a valve is partially closed, then you can experience significant pressure loss across the valve. If the pressure problem is isolated to one particular zone on your system, then make sure that valve is fully open.
If you have checked all of the previous items and are still experiencing pressure problems, call WBWCD. It is possible that we may have a problem with our system in your area.