Does your sprinkler system have low pressure in one zone? Consistently low pressure, but in only one zone, can be frustrating, as the problem will soon leave a brown spot in your lawn, as its water doesn’t get as far as it should. Intermittent low pressure can be even more frustrating. It seems like the second you go to look, the sprinkler picks back up again. Here’s how to troubleshoot your low-pressure zone and find out what the problem is.

1. Improper Installation

If this one zone hasn’t had proper water pressure since it was installed, the installer likely made a mistake. Your installer may have connected two zones to use the same water pressure, which often results in one zone having significantly less pressure. Alternatively, they may have installed a faulty valve, not programmed the timer correctly, or made some other mistake. While we can fix some installation mistakes quite easily, others involve re-running the actual pipe. It all depends on what time of mistake your installer made.

2. Leaks

Often when your sprinkler system was running fine, and then one zone began to lose water pressure, the culprit is a leak in the zone’s lines or a leak at a nozzle or two. Leaking nozzles won’t produce the same water pressure and need to be replaced, which is fairly simple. Finding a leak in the line is a little more challenging, but still fixable. One thing to consider is that if your system has been in place for a long time, the zone’s pipes may have been crushed by tree roots. If so, you may need to replace the pipes and take further action to protect them.

3. Clogs

Just like leaks, clogs may also affect only one zone in your sprinkler system. Debris that has worked its way into the nozzles is one cause of a clog. Or, you may have a clog created by a broken valve, that is remaining closed when it should open to allow water through. Cleaning out the debris in the sprinkler is typically simple. Finding a clog is a little less so.

4. Loose Solenoid

One reason that the valve for one of your systems is remaining closed, or closing intermittently, is a loose solenoid. A solenoid is an electrical device that is connected to the valve and tells the valve when to open based on electrical signals from the timer. If the solenoid does not have complete contact with the valve, its signal is less effective. It may only partially open the valve, or it may keep the valve closed altogether.

5. Timer Problems

Timer problems are the most common cause of intermittent low pressure in one sprinkler system zone. The timer for this zone may be a bit behind the others, causing a delay for full water pressure to reach the affected zone. Or, the timer may turn the zone on and off a few times or may not turn it on at all.

Unfortunately, very few of these causes of low pressure in one zone can be tackled without the help of a professional. Once you have an idea of what’s going on, give the professionals a call to confirm your hunch.