With cooler weather on the way it’s time to make sure your irrigation system is ready for winter. One of the first things to do is inspect it for any damage and make the necessary repairs. Leaks in sprinklers and pipes will waste water.
Here are some of the issues to look for during an inspection:
- Sprinkler heads popping up only partially or not at all.
- Sprinkler heads spraying in all directions.
- Obvious broken or damaged sprinkler parts.
- Nozzle heads clogged.
- Rotor heads not rotating or rotating incorrectly.
- Water pressure problems (too little water from sprinklers or misting).
- Water bubbling around sprinkler heads.
- Dry spots when sprinklers running.
- Very wet or soft areas, or depressions in the ground.
- Water bubbling up from the ground when the system is running.
- Zones not turning on or shutting down.
- Electrical and controller issues.
- Rain, freeze, or soil moisture sensors damaged or not working properly.
- Wet valve boxes.
If the causes for some of these problems are easy to diagnose, the do-it-yourself homeowner can fix them. However, some of these repairs involving broken pipes, leaks, control valves, controllers, and wiring should be done by an irrigation professional. He can even do the inspection and repairs, and then winterize the system, including setting up the controller for reduced watering times.
Winterizing Your System
Once the inspection and any repairs are done, it’s time to winterize the system. In this part of Texas winters are relatively mild, and it’s not necessary to drain the underground irrigation pipes or blow them out with compressed air. The soil insulates the pipes, and the ground doesn’t freeze very deep. But we do experience freezing temperatures and hard freezes (when the air temperature falls to 28°F or lower and stays below 32°F long enough to cause ice formation in standing water), so we want to protect the system during those times and still be able to irrigate during the winter.
Valves and Above-Ground Pipes
Usually the sprinkler manifold assembly and valves are below ground and protected in a valve box, but sometimes the valves are located above ground. In this case they should be wrapped and covered with an insulating pouch.
Above-ground pipes need to be insulated from freezing temperatures. You can wrap them in fiberglass insulation, or apply self-sticking foam insulating tape. Foam insulating tubes also offer good protection.
When closed, the isolation valve isolates the irrigation system from the main water supply. It must be “freeze-proof”, and can be located inside a heated room, outside above ground, or buried below the frost line. If above ground, wrap it with either foam insulation wrap or fiberglass pipe insulation wrap, and keep the wrap dry with heavy rubber tape.
Backflow Prevention Assemblies
You can turn off your backflow prevention assembly (BPA) and drain it, but if you want to irrigate during the winter it’s recommended you wrap and insulate it instead. Use foam pipe wrap taped with heavy rubber tape, or fiberglass pipe insulation wrap held in place with plastic or heavy rubber tape for waterproofing. Don’t block the air vents and drain outlets.
You can then cover the BPA with an insulating pouch that has an opening at the bottom. An insulated enclosure adds further freeze protection on top of the pouch — some even look like decorative rocks.
Use the “seasonal adjust” feature on your controller for winter irrigation. This changes the zone run times to a percentage of the programmed schedule set up for the hottest time of the year. For lawns that go dormant, adjust the programming to water once or twice a month.
Different types of sensors connected to controllers help even more with winter irrigation:
Rain sensors turn off your system when it starts to rain, using either a predetermined quantity of moisture, or a time factor — usually within the first few minutes of rain. In Texas the Texas Commission on Environmental Quality (TCEQ) requires that all new automated irrigation systems, and any repairs involving replacement controllers, must include rain or moisture shut-off devices (Title 30 TAC Section 344.62 (j)).
Freeze sensors turn off your irrigation when a set temperature is reached (e.g. 37°F). Some sensors give you a choice of low temperature points (e.g. 33°F to 41°F). Rain and freeze sensors are often combined.
Wind sensors interrupt irrigation when the wind reaches a programmed speed. Usually there are adjustable shutdown speeds.
Soil moisture sensors interrupt irrigation when the moisture in the root zone is above a specified content. Some are combined with a freeze sensor that stops irrigation when a chosen temperature is reached (e.g. between 37°F-45°F).
What to do When a Hard Freeze is Forecast
When a hard freeze is forecast, take the following steps to protect your irrigation system:
- Shut off the water supply to the irrigation system at the isolation valve.
- Stop the controller by turning it to the “rain”, “delay watering”, or “off” setting. With some types you have to suspend the zones for a certain amount of time to get it to shut down. Your programming will still remain intact. With mechanical controllers, use the “off” position. This will cause a loss of settings, and you’ll have to reprogram when you start the system again.
- Gear-drive rotor sprinklers installed above ground need to be drained so they don’t freeze and rupture. It’s necessary to install a drain valve on the sprinkler supply pipe if the water doesn’t drain out on its own. The check valves on rotor sprinklers can also prevent water from draining out — remove the rotors, shake out the water, and replace them.
Unless you’ve overseeded with rye grass, your lawn will go dormant over the winter, and won’t need as much water. You should irrigate it once or twice a month, however, to maintain a healthy root system for new growth in the spring.
Keeping an active irrigation system over the winter also prevents:
- Algae growing in stagnant pipe water, clogging sprinklers in the spring.
- Roots growing into sprinklers.
- Insects laying eggs in sprinklers.
- Stuck valves.
- Dried out and split valve diaphragms.
- Dried and cracked sprinkler seals.
- Dirt and dust in sprinklers.
Running your sprinklers during the winter keeps your irrigation system healthy by lubricating seals and diaphragms, moving stagnant water out of pipes, and blowing roots, dirt, and insects out of the system.
Call the experts at South Austin Irrigation at (512) 534-7449 or fill out our Service Request form for professional maintenance and repair to your sprinkler system.