When spring is busting out all over, don't let your irrigation system.

Picture this: It's springtime! Finally those long, cold, barren days of winter have melted away. You realize that it's time to fire up your irrigation system. You open the supply valve wide, turn on the timer, then, stand back to watch in horror as a geyser erupts in the middle of your yard. In the "flash flood" inspired panic you rush to shut the water off again. What happened? Well, in your spring induced excitement, you neglected to properly start up your irrigation system after its long winter nap. Fortunately, this scenario is easy to avoid. Just a few simple steps before you turn on your irrigation system will protect it from immediate and unseen damage, as well as, making it more reliable year after year.

Don't Get Hammered!
The greatest threat to your irrigation system, during initial start-up, is water hammer. You may already be aware of water hammer if you have "clanging" plumbing in your house. That "knock" is produced by a surge of air pressure caused by the rush of water suddenly flowing into an empty pipe, giving the air in the pipes no time to escape. This causes the banging you hear. But that is just the outward indication; inside the pipes the surge pressures can reach as much as 15 times the designed operating pressure of the system. These surge pressures can burst fittings and cause sprinklers to literally blow right out of the ground. Worse still, even if your system doesn't blow like Old Faithful from these surge pressures, you may be risking system failure later on when you are away on vacation, or in the peak summer months when you need your irrigation system the most.

Good things come to those who wait.
How do you protect yourself? Before actually "recharging" your irrigation pipes, use a shovel, or a spade to confirm that the soil is frost-free to a full twelve inches below the surface. Filling your system too early, with the ground still frozen, can cause unseen and hard to fix freeze damage to your pipes. So, don't rush.
When you are sure the soil in your yard is ready, it is time to recharge your system. The first thing to do is be sure you have a collection of spare irrigation parts: fittings, risers, sprinkler heads and nozzles on hand just in case they are needed. Include some extra PVC and/or poly pipe, primer, and cement as well. It is better to have these things available and not need them, than to need them and not have them. Finally, if you have an automatic controller, replace the batteries that are used to preserve your settings if the timer uses them.

"Houston, we have ignition." Now that everything is ready and accounted for, it is time to start filling. If your irrigation system isn't equipped with air pressure relief valves or drains, remove the sprinkler heads located at the highest point of each zone. This will allow the air in the pipes to be pushed out of the system during refilling.
Begin filling the system very slowly, this will minimize surge pressure and let you check the function of all the shutoff and zone valves that may be present, without too much pressure in the lines. Begin the process by filling the main line of the irrigation system (located between the water source and the zone valves) with water. Slowly open the shutoff valve that controls the water supply to the entire system. A quarter-turn or so is all you need. Take your time and remember that the water has to travel the entire length of your main line.
Once the main line is filled, proceed with filling each zone, again by very slowly opening the zone valve manually. Manual operation of automatic zone valves differs from manufacturer to manufacturer, so read the product literature for those valves for instructions on how to manually operate the valve. Toro valves use an internal or external bleed screw to accomplish this. Watch the spots where you removed the sprinklers on each zone. When the water pouring out of the open riser runs clear and free of air bubbles, close off the zone valve. It may take as long as 30 minutes to carefully fill a zone. Once the water to that zone is shut off, either close the air-relief valve(s) or replace the sprinkler head(s) you removed, beginning with those closest to the water source. After that is done, move on to the next zone and repeat the process until all the zones are filled.

Do a little rain dance.
Once you have filled the entire irrigation system, run each zone for two minutes. This lets you test your automatic timer, while flushing out any remaining air, and checking to be sure all the heads are spraying properly. As each zone is operated, check the area around the valves and sprinkler heads to be sure that there are no leaks or breaks in the system and that all sprinklers are level with the ground and spraying correctly. (You may get wet doing this…have fun with it!) Once everything is filled and operating correctly, you can then open the main supply valve to its full operating position.

Finally, check to be sure your timer programs are still accurate, and if so, relax, and let the system take over from here - you've done enough.

This may look like a long list of things to remember, but after doing it once, it will be simple and easy to remember. Keep in mind that doing things right, once a year, may well save you a lot more annoyance and expense later on.