Lawn Watering Guide

More than half of the water used by Mansfield households goes into lawns. Most people either water too much or too often. SAVE WATER, MONEY, and WORK by following this easy rule of thumb and by knowing these tips.

  • SprinklerDetermine the precipitation rate of each zone in your irrigation system. Precipitation rate is the rate at which water is applied to the soil, usually measured in inches per hour.
  • Determine the infiltration rate of the soil in each zone. The infiltration rate is the rate at which water enters the soil, again, usually measured in inches per hour. Applying water to the soil faster than it can be taken in will result in runoff, which not only wastes water but can pollute surface water lakes and streams.
  • Determine the water requirements of your lawn and plants. A licensed irrigator or certified landscape irrigation auditor/manager should be able to assist you.
  • Knowing how much water your system applies, the rate at which the soil can accept water, and the amount of water your turf and plants require will enable you to make educated decisions about your outdoor watering.

When Can I Water?

City Ordinance:

  • The City of Mansfield's Water Conservation Plan prohibits outdoor watering with an irrigation system between the hours of 10a.m. and 6p.m year-round.
  • According to the Texas A&M University School of Irrigation, the optimum time to water is between 3a.m. and 6a.m.

Precipitation Rate?

Check For Yourself:

  • Set 3-5 empty cans at different distances from your sprinkler. Tuna cans work best.
  • Run sprinklers for 30 minutes
  • Add the inches of water in all cans. Divide total inches by the number of cans.
  • Now you know how many inches of water your sprinkler applies per hour.
  • Adjust that time to determine how long you'll need to run your sprinkler to apply one inch of water.

Infiltration Rate?

Check For Yourself:

  • Take any empty coffee can and open it on both ends. You may also use a wide diameter pipe or other solid cylindrical device.
  • Push one end of the can into the soil in your yard or flowerbed.
  • Using a watch, pitcher of water, and tape measure, fill the can to a depth of four inches.
  • Allow the water to soak into the soil for thirty minutes.
  • Using the tape measure, determine the amount of water remaining and subtract it from the four inches you started with. Now you know the infiltration rate of your soil in inches per ? hour.
  • Adjust that time to determine how many inches your soil can accept per hour.
  • This number is important because you don't want to apply water faster than your soil can accept it.
  • Using low output sprinkler heads, bubblers, or drip irrigation systems help prevent runoff and are efficient ways to apply water.

Water Requirements?

Check With A Professional:

If you prefer to determine the water needs of your turf and/or plants yourself, a basic (and I do mean basic) rule of thumb is one inch per week. We strongly recommend that you consult with professionals when determining your watering needs.

A specific plant's watering needs depends on a number of factors. Take a look at the formula below:

  • ETplant = ETo * Kc * Allowable Stress
  • When:
    • ETplant = the amount of water you should apply to replace the "normal" water loss from your specific turf or plant
    • ETo = the water needs of a hypothetical reference grass which is four inches tall, well watered, and in deep soil. This represents a perfect grass.
    • Kc = the crop or plant coefficient for a specific turf or plant.
    • Allowable Stress = the adjustment factor is almost always used in turf to modify the Kc for allowable stress. 60% is used in most sites and produces a good quality turf with no "visible" stress.

A licensed irrigator or certified landscape irrigation auditor/manager should be able to assist you.

Can Someone Help Me?

For help understanding the information above please feel free to contact city personnel:

The City of Mansfield has partnered with W.I.S.E Guys to offer free irrigation evaluations to our residents using licensed irrigators that have gone through a rigorous vetting and training program.

To schedule your FREE irrigation evaluation, please sign up here: