During January 2010, the Houston metropolitan area experienced temperatures below freezing for 18+ consecutive hours. This was extremely rare, but it resulted in thousands of sprinkler systems being damaged since they had not been shut off and drained properly beforehand.


“Normally” southern Texas weather is very mild compared to our friends in northern states. However, I urge all of my customers to winterize their systems the first week of December. This time is when lawns and plants usually go dormant, but did you know your monthly sewer rates are prorated on your December through February water consumption?


Our semi-tropical weather means we don’t have to worry about pipes freezing below the ground, but we must protect backflow preventers located above ground level. You’ve probably seen sprinkler systems “broken” and spewing water out for hours after this hard freeze.


To prevent this from happening to you, I want to share my procedures on properly winterizing your sprinkler system. This takes two minutes to complete, but first you need to know to learn the terminology.


Don’t be surprised if your sprinkler contractor “forgot” to install your system according to standards established by the Texas Administrative code. If your system is as described, don’t panic. We can come out and modify it for you!


All homes have a water meter with a shut off valve inside a rectangular green valve box which is usually located on the property line, near the curb. These are alternately called main water shut-off, city water meter, or water main. They are located along the street. If you live on a cul-de-sac, each home might have its own separate box. People living on a regular street normally share a box with their neighbors. Attached is a picture to help you identify where your city water meter is located. To begin the process, all boxes have a round hole where you can insert your finger or channel locks to pry the lid off.
#1 City water main valve box
I believe most valve boxes have never been opened by the homeowner, so they don’t know what to expect. Below is the valve box at my home, which is probably just like yours!

Picture #2: The first surprise

This valve box is filled with water which obscures the water meter and shut off valve. Valve boxes attract water for a variety of reasons: being installed in a swale or low spot, water following the trench back from the house, or over-watering. You can use an old cup or can to bale the water out. Be patient since it might hold several gallons of water. Once the water is removed, here’s what you should see.

Picture #3: All I see is mud
Here’s your next surprise… Where there used to be water, there is now mud. Don’t get discouraged, since once you clean your valve box out, you should never have to do it again! Use a small hand shovel to dig all around the meter, as there could be sharp items buried in the mud. The meter looks like a clock dial, but you are looking for a straight piece of metal BEFORE the meter. That is the shut off valve. It’s about 1.5″ long by .5″ wide and is reflected in the next picture.

Picture #4: That’s it?

The arrow reflects the shut-off valve. If it’s straight (in-line) with the water meter, it is turned on. Homeowners have two options for turning their water off, if it becomes necessary. A crescent wrench or water shut-off key will do the job. The latter item is available at Home Depot or Lowes.


One disclaimer… If your house is more than 5 years old, there’s a possibility your valve could be frozen. When something has not been used in a while, it tends to become stuck in its open position and all of your gallant attempts turning may not budge it. If this occurs, most local MUD (Metropolitan Utility Districts) have mobile staff that carry industrial strength shut-off keys, and can turn it off for you at no cost.


The reason you need to know where your water shut-off is in case your sprinkler system does not have an isolation valve before the PVB (Pressure Vacuum Breaker) to shut the sprinkler water off. Here’s a picture of what this valve looks like. It should be located inside of a valve box. They are normally located “close” to the city water valve box or at the base of the PVB, like the picture below.

An isolation valve permits the sprinkler water line to be isolated and turned off, while your house water stays on. This is very important to remember, should your PVB freeze and crack, since without one, you MUST TURN OFF YOUR WATER AT THE STREET, which means no water to the entire house!
You might be asking why you need an isolation valve if you already have two shut-off handles on your back flow prevention device. In our tropical location, metal rusts and corrodes over an extended period of time. Handles on a PVB or DCV break off within several years of installation. You should go outside and check the condition of yours prior to an emergency. Try turning one of the handles and see if it is frozen, stiff, or hopefully turns freely.
Chances are, if it’s heavily rusted, when you attempt to turn it, it will break off. Now you can see the value of an isolation valve. Plastic is impervious to rust and should be your primary method of turning your sprinklers on and off, so the rust issue becomes irrelevant. Older systems did not have this requirement, but they are now required under Texas Administrative Code, Title 30, Part 1, Chapter 344, Sub-chapter 7, Rule §344.62. This section spells out the minimum standards for sprinkler systems.
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Specifically, look at….

(k) Isolation valve. All new irrigation systems must include an isolation valve between the water meter and the backflow prevention device.

If you don’t currently have an isolation valve or your metal shut-off handles on your PVB or DCV are rusty or inoperative, contact us and we can retro-fit this onto your system within our service area.

Finally, we are ready to shut the water off. Here are the procedures:

1. Locate your isolation valve and turn it 90 degrees clockwise to shut off the sprinkler water.

2. Using a straight edged screwdriver, turn ALL pit cocks 90 degrees horizontically to open them up. All PVB and DCV pit cocks rotate 360 degrees, so there’s no right or wrong way to turn them. Once you do this, you will hear the vacuum break and water will start to drain out of the pit cocks. Leave them open until you want to turn your water back on, so any trapped water has an increased chance to evaporate

3. Once the vacuum is broken, most remaining water can freeze and expand without harming the brass fitting. If the water was left on, the water turns to ice and expands, breaking the bonnet or brass to relieve the built-up pressure.

4. The final step is to turn on one zone on your controller for 10 minutes to vent the water underground from the discharge side of the PVB or DCV. Your sprinklers will not come on, but will simply dribble water out of the lowest head which you will not see.


Some closing items you should consider:

1. Are your PVB or DCV shut-off handles capable of being shut off in an emergency? If they are similar to these, you should consider getting an isolation valve installed as a pre-emptive measure before the next freeze occurs.
2. Is your PVB or DCV insulated like the next picture? If not, we urge you to get it insulated. As a FYI, insulation protects the PVC pipe from the ultra-violet light which makes the PVC brittle and prone to damage.
3. Are the protective shipping caps removed from your PVB or DCV? If not, it is MUCH harder to get them off when it’s below freezing. They should be removed at installation but are often overlooked, as the following picture depicts, since they serve no useful purpose.
4. Are your pit cocks facing the correct direction (downward)? If not, water does not drain uphill. If DCV is installed incorrectly, we can correct this mistake for you.
5. Also, are your PVB pit cocks accessible with a screw driver? Some installers neglect to face them the correct way.

Green Earth Sprinklers is your Woodlands based sprinkler system and we have 1,300 satisfied customers whom we e-mail each December, along with directions on how to winterize their sprinkler system.

If we can help prepare you for the upcoming winter season, please give us a call at (281) 298-5050, visit our website or send us an email via our web site at and we will respond to your needs in a timely and professional manner.

Contact us Today!