Understanding Your
Underground Sprinkler System
An underground sprinkler system installed by Katy Water Works is not only a convenient way to water your plants and lawn, it also makes the very most efficient use of water. This article will give you an overview of the steps involved in designing and installing a quality underground sprinkler system.
In this article you will find information about:

Types of Sprinkler Systems
Planning Your Sprinkler System
Installing Your Sprinkler System


  • The water pressure in most residential systems isn’t great enough to water an entire lawn at once. As a result, most systems are divided into circuits or zones, each with its own electronic solenoid control valve. Control valves are operated by an electronic controller that turns each circuit or zone on and off according to the schedule you set.
  • The system consists of standard PVC pipe running from your existing water supply line. At each sprinkler, the pipe connects to a fitting that feeds the sprinkler head. Sprinkler heads are designed to throw water in a full circle, a half circle or a quarter circle ( there are also adjustable 0-360 degree nozzles as well as side-strips and more ).

    There are basically three types of heads:

    Micro-sprayers: Small But Effective

    Micro-sprayers are adjustable sprinkler heads that can provide a dribble or a spray up to 10 feet. These sprinkler heads are mostly used to water flowerbeds, foundation plants and areas that have limited water needs. Micro-sprayer heads come in a variety of fan patterns up to 360 degrees.

    Pop-up Heads: The Industry Standard

    Pop-up sprinkler heads hide underground when not in use. When the irrigation system is turned on, these sprinkler heads use water pressure to rise up out of the ground. Water pressure is also used to turn the gears in rotary pop-up heads. Pop up heads can cover an area of up to 35 feet and are used to water large areas of turf grass.

    Pop up sprinkler heads come in both rotary and fixed spray models. Pop-up rotary heads can be adjusted to fit a custom spray pattern or can be allowed to cover a full circle. Fixed spray pop-up heads come in quarter, half and full circle patterns.

    Impact heads: A Blast From The Past

    In an impact sprinkler head, a mechanical arm interrupts the water flow causing the water to form a spray pattern and moving the head around in a circle. Impact heads have a range of up to 45 feet and are useful in covering large areas.


  • The first step in planning your system is to check with your local building department and get any permits you may need. Then make a sketch of your property, showing the locations of all structures, walkways and driveways, trees and shrubs. Call your local utility companies and have them come out and mark the location of buried gas, electrical and telephone lines. Note those locations on your sketch.

    ** The plan below is an example of one of our designs. Click to see full size.
    Click this sample design to enlarge.
  • Next, determine your water pressure and flow rate. Use a pressure gauge and attach it to a hose bibb. Turn the water on full (with all other water in the house off) to find the pressure. Systems vary, but you’ll probably need a minimum of 20 pounds per square inch (psi) pressure to install sprinklers.
  • Check the flow rate by placing a 1 gallon bucket under a hose bibb, turning the water on full (with all other water in the house off) and time how long it takes to fill the bucket. Divide the number of seconds by 60 to find the gallons per minute (gpm) capacity of your line. The result of this test will determine the size of each sprinkler circuit.
  • Then plot the locations of sprinkler heads on your sketch. Multiply the throw distance of the heads (usually 15′) by 1.4 to find the spacing between sprinkler heads so the areas covered by each head overlap. In windy areas, space the sprinkler heads the same as the throw rating.
  • Finally, divide the system into circuits or zones. The manufacturer’s instructions will include an output chart that gives you a gpm rating for each sprinkler head. Divide the gpm capacity of your water line by the rating of each head to find the number of sprinkler heads that you can put on each circuit or zone. Never combine different types of sprinkler heads (e.g., lawn sprinklers with low-shrub sprinklers or gear drives) on the same circuit.

    Types of Sprinkler Systems
    Planning Your Sprinkler System
    Installing Your Sprinkler System


    At its most basic level, a sprinkler system consists of a relatively few main components. We'll start with the controller. This is an electronic, computerized unit that is the "brains" behind the sprinkler system. The controller utilizes a timer that tells your system which set of sprinkler heads need to turn on when, and for how long. It is connected to a set of valves that regulate the flow of water into a specific "zone" in your sprinkler system. The valves are tied directly into your water system and act like faucets that turn off and on when told to by the controller.
    These valves then feed water into the rest of the sprinkler system, which is typically composed of undersurface pipes that lead to the actual sprinkler heads. The sprinkler heads are normally placed near ground level when not in use, and then pop-up when the water pressure fills the pipes that feed them...so there you have it, the essence of a sprinkler system.
    Although there a number of "do-it-yourself" sprinkler system kits on the market, the complexity of a properly designed, installed and maintained system, precludes the ability and expertise of the average homeowner. For instance, how many homeowners would know what the local regulations and specifications are? Are there permits required? Which backflow device is needed for the specific application; PVB, RP or double check? Is PVC or poly pipe called for? How many and what type of valves are needed? What type of rotor heads do you need; stream rotors, gear driven rotors or impact-style rotors, and where do you place them? And what about "spray" or "mist" type heads, drip irrigation, rain sensors, etc. etc.
    Katy Water Works can answer to these questions and many others. We will also be able analyze everything from your soil conditions to which parts of your yard get the most sun and/or shade. We will also consider the slope of your property, the various types of landscaping you have and their water requirements as we plan and design an efficient system for your home.
    Zoning Your Lawn
    Irrigation zones are an element of landscape irrigation design that allows your system to target water distribution with precision. The premise behind the landscape irrigation design concept of "irrigation zones" is a simple element of planning the system. Zoning basically ensures that Zone A of your lawn should get X amount of water while Zone B should only receive Y amount, and so on.
    Establishing irrigation zones allows your sprinkler system to be programmed accordingly. This ability to discharge more precise amounts of water in a targeted area further promotes water conservation and costs savings.
    Sprinkler System Water Conservation Tips
    Did you ever dream that you could actually save water through the use of an irrigation system? Perhaps not. But an irrigation system that is properly designed, installed and maintained, will help minimize the amount of water you use, while keeping your lawn and landscape looking good and healthy.
    Here a few tips to help you have a lush, green landscape without draining the rivers and your bank account...
    1. Don't drown everything
      The greatest waste of water comes from applying too much, too often. Much of the water is never absorbed. Instead of watering for a long session, water a few times for shorter periods and take 15-minute breaks between each session. This will allow time for the water to soak in, while minimizing run off. (Especially in the hard clay soil of our area).
    2. Watch the clock
      Optimum watering hours are from 5 a.m. to 10 a.m., when the sun is low winds are calm and temperatures are cool. Midday watering tends to be less efficient due to water loss through evaporation and windy conditions during the day. Watering during evening hours isn't the best idea either. Wet lawns and plant leaves can remain wet overnight-an irresistible invitation for fungus and other diseases to develop and grow. Watering during early morning hours allows everything to dry out throughout the day.
    3. Divide by zones
      Different plants need different amounts of water. Divide your yard and landscape areas into separate irrigation zones so grass can be watered separately and more frequently than groundcovers, shrubs and trees. Both sprinkler and drip irrigation can be incorporated to achieve more efficient use of water.
    4. Water only things that grow
      With a subsurface sprinkler system, proper sprinkler head alignment is paramount in order to water only living plants, not sidewalks, driveways or the street. A properly adjusted sprinkler head should spray large droplets of water instead of a fine mist. This will minimize evaporation and wind drift.
    5. Consider dripping
      When it comes to watering individual trees, flowerbeds, potted containers or other non-grassy areas, consider applying water directly to the roots using low volume drip irrigation. This approach will reduce water waste from evaporation or runoff. It will also prevent unwanted weeds from growing. A basic drip system consists of a series of tubes that have holes at intervals. The location of the open holes is tailored to irrigate specific plants more efficiently. For instance, if you have certain plants spaced at two-foot intervals, the corresponding holes in the drip system will also be spaced at two-foot intervals. Water will be distributed only where the plants are stationed and not in the areas between them.
    6. Perform routine inspections
      If you're watering at the proper time of day (early morning hours), a problem may occur and not be discovered until it is too late. Periodically examining your sprinklers to make certain everything is in proper working order can save a lot of headaches. A clogged head or a torn line can wreak havoc on your landscape and water bill.
    7. Be rain and season smart
      Always adjust your sprinkler system as the seasons and the weather change. An easy way to accomplish this is to install a shut-off device in your system that automatically detects rain or moisture. These devices are relatively inexpensive and enable you to take advantage of Mother Nature's watering without having to pay for it.

      Types of Sprinkler Systems
      Planning Your Sprinkler System
      Installing Your Sprinkler System