How Long Should I Water My Lawn?

Rotating yellow sprinkler watering grass lawn

The Spruce / Steven Merkel

Learning how long to water your lawn is important for several reasons. Too much or too little water can result in a less than ideal appearance with dead or dried patches that invite weeds. Overwatering can also raise your water bill significantly so it pays off to have a fairly close idea of how much water your lawn requires to maintain green, good health. There are several factors to consider which include your soil and your specific growing zone.

Water Requirements for Lawns

As a general rule, lawn grass needs about one inch of water per week. This figure may change, though, depending on your soil type. Proper drainage in goes in hand-in-hand with meeting the water requirement of a lawn. To achieve proper drainage, a balance must be struck:

  • If the composition of your soil is too sandy, water will run right through it as if it were a sieve. So giving your lawn one inch of water per week if it is growing in this kind of soil will not keep it adequately irrigated.
  • But if your soil type has too much clay, it will retain too much water. Grassroots do not like to sit in water constantly. Diseases can result from this condition.

A loamy soil strikes the ideal balance for achieving proper drainage. It has sufficient organic matter for the right amount of water retention, and will not lead to waterlogged conditions.

How Long to Water Your Lawn

The important question for lawn health is not so much how long to water your lawn at any given time as it is how much water to give your lawn.

To answer the question, it will take your sprinklers about one hour to put out the required one inch of water per week. Establishing a good irrigation schedule will help you achieve your lawn's water requirements.

A related question is how often to water your lawn. You do not have to provide the required one inch per week all at once. Instead, you can water for 30 minutes twice a week. But some experts advise against extending irrigation sessions beyond that (for example, watering for 20 minutes three different times a week). Watering too frequently keeps roots too close to the surface. Less frequent watering encourages them to reach down deeper in search of water and aA deeper root system is less susceptible to heat stress and pest damage.


There is a simple way to measure how much water your grass is getting. Place a reservoir (a bowl, pan, empty plastic coffee container, etc.) on the lawn within the spray area of your sprinkler. Turn the sprinkler on, and keep track of time. Turn the sprinkler off after 30 minutes and measure the water level in your reservoir. If you are not getting the projected half an inch, adjust your irrigation schedule accordingly, either increasing or decreasing watering time.

The type of sprinkler you use affects exactly how long it will take you to water your lawn, so, again, be prepared to adjust your irrigation schedule accordingly. It will take slightly longer with the type of oscillating sprinkler that you attach to a garden hose because you have to move it around (on large lawns) to irrigate each and every portion of the lawn. It will take less time if you have an automatic irrigation system because such a system is designed to cover the whole lawn all at once.

Knowing When to Water Your Lawn

The best time of day to water is early morning. When the sun is low in the sky, there will be less evaporation, giving the water a chance to seep down into the root zone. The grass blades will have all day to dry out before nightfall. The longer grass blades stay wet, the greater the chance they can succumb to fungal diseases.

Artificial irrigation should be used only to supplement rainfall. Do not water your lawn if rain is coming, it is currently raining, or it has just rained.

You will not have to supply the same amount of artificial irrigation year-round. Grass needs that one inch of water per week when the weather is hot, and/or the grass is actively growing.

So, for example, for a cool-season grass in the Northeast, you will be watering most in late spring, in summer, and in early fall. However, do continue to water throughout fall to make up for the fact that your grass will largely be deprived of water during the winter.

Signs Your Lawn Is Being Over-Watered or Under-Watered

Over-watering is just as detrimental to the health of your lawn as under-watering. Some issues may be caused by either extreme so it might be necessary to look at several problem areas in your lawn to determine if the grass is too wet or too dry.

Signs of Under-Watering

  • The grass turns yellow.
  • The grass is limp. When you walk on the grass, it fails to bounce back up afterward.

Signs of Over-Watering

  • The grass turns yellow.
  • Bare spots develop in the lawn.
  • Mushrooms are growing in the lawn.
  • The turf has a spongey feel when you tread upon it.
  • There is visible runoff.