How Long Should You Water Your Lawn?

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In This Article

How much water your lawn really needs

Best Lawn Sprinkler

Measuring your sprinkler output

Finding the right sprinkler runtime

The best time of day to water your grass

Adjusting for rainfall

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Most lawns need about 1 to 1.5 inches of water per week, which usually means running sprinklers for around 20 to 45 minutes per session, two to three times per week. However, the exact timing depends on factors like grass type, soil conditions, sprinkler output, temperature, and recent rainfall.

Watering too little can leave grass dry, brittle, and brown, while overwatering can create soggy soil that encourages fungus, pests, and shallow root growth. But you don’t have to overcomplicate it, either. Once you know how much water your sprinkler system puts out, and how quickly your soil absorbs moisture, it’s much easier to set up a healthy watering routine.

This guide breaks down how long to run sprinklers, how often to water, and how to adjust your schedule throughout the year to keep your lawn green without wasting water.

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How much water your lawn really needs

In general (and including rainfall), lawns need around 1 to 1.5 inches of water every week. This will change depending on your type of grass, soil conditions, climate, and the time of year. For example, during hot summer weather or drought periods, lawns may need more frequent watering, while cooler temperatures and regular rainfall can significantly reduce your watering needs.

By and large, cool-season grasses like Kentucky bluegrass and fescue need slightly more water than warm-season grasses like Bermuda or zoysia. Soil type also matters. Sandy soil drains quickly and may require more frequent watering, while clay soil holds moisture longer but absorbs water more slowly.

As a general rule:

Most lawns: 1 to 1.5 inches weekly

Warm-season grass: often needs less water

Sandy soil: water more often for shorter periods

Clay soil: water less often but for longer sessions

Instead of watering lightly every day, aim for deeper watering a few times per week to encourage stronger root grass growth and better drought tolerance.

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Measuring your sprinkler output

To figure out how long your sprinklers should run, you first need to know how much water they actually put down. An easy way to measure this is with the “tuna can test.”

Place a few empty tuna cans or shallow containers around the lawn and run the sprinklers for 20 minutes. Then measure the water depth in each container and calculate the average using this formula:

Average water depth × 3 = sprinkler output per hour

For example, if the containers collect an average of 0.25 inches of water in 20 minutes, your sprinklers apply about 0.75 inches of water per hour. Knowing this makes it much easier to set an accurate watering schedule without overdoing it.

Finding the right sprinkler runtime

Once you know how much water your lawn needs and how much your sprinklers put out, you can calculate how long to run the system each week. Use this formula to calculate how long to run the sprinklers:

Weekly watering need ÷ sprinkler output = total runtime per week

For example, if your lawn needs 1 inch of water weekly and your sprinklers put out 0.75 inches per hour, you’ll need to run them for about 80 minutes total each week.

It’s usually best to split that time into two or three watering sessions rather than watering every day. Deep, less frequent watering encourages stronger roots and helps prevent shallow, stressed grass.

The best time of day to water your grass

The best time to water grass is early morning, ideally between 6 am and 10 am. Cooler temperatures help more water reach the soil before it evaporates.

Avoid watering during the hottest part of the day, when much of the water can evaporate before soaking into the ground. Watering late at night also isn’t ideal, since damp grass sitting overnight can encourage fungus and other lawn issues.

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Everything you need to water your lawn the right way. Bob Vila has partnered with Sunday to get your lawn exactly what it needs to thrive.

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Adjusting for rainfall

Photo: JJ Gouin via Adobe Stock

Yes, rain does count toward your lawn’s weekly watering total, so you may not need to run sprinklers as long after a storm. A simple way to adjust your schedule is to calculate the following:

Weekly watering goal − rainfall = watering needed from sprinklers

For example, if your lawn needs 1 inch of water weekly and you get 0.5 inch of rain, your sprinklers only need to supply the remaining 0.5 inch. A rain gauge or smart sprinkler controller can make these adjustments even easier.

Signs of overwatering and underwatering

A lawn that’s not getting the correct amount of water will usually show signs of stress pretty quickly.

Signs of underwatering:

Brown or dry patches

Curling grass blades

Grass that stays flattened after being stepped on

Signs of overwatering:

Soggy or spongy soil

Mushrooms or fungal growth

Lots of weeds or thatch

Yellowing grass despite frequent watering

If you notice any of these issues, adjusting your watering schedule is often the quickest fix.

DIY Lawn Care. Simplified.

Everything you need to water your lawn the right way. Bob Vila has partnered with Sunday to get your lawn exactly what it needs to thrive.

START GROWING

Key takeaway: Keeping a lawn healthy doesn’t require watering every day or running sprinklers for hours at a time. In most cases, a few deep watering sessions each week are enough to support strong roots and greener grass. By measuring your sprinkler output, adjusting for rainfall, and watching for signs of stress, you can build a watering schedule that keeps your lawn healthy without wasting water.

FAQ

Q. Can you overwater grass? Yes, if the turf never dries between watering, the moisture can choke out oxygen. Watering too heavily can wash away soil nutrients or cause water to pool in low spots, which is bad for the lawn and your water bill. Water less often for a little longer and watch for signs of overwatering or fungal activity.

Q. How can you tell if you’ve watered your lawn enough? Step on the grass. If it springs back, it does not need water. Look for signs of trouble, and calculate approximate lawn watering time with one of the formulas in this article, invest in a soil moisture meter or water sensing technology, or check with your local cooperative extension office for more help if unsure.

Q. Does grass need to be watered every day? No. Only grass seed should need watering every day. Once seeds, sod, or plugs are established, cut back on the watering. Bermudagrass can wait 5 to 10 days between watering and bounce right back, for example.

Q. Can brown grass turn green again? Yes. Most grasses go dormant in winter (and turn brown), then begin to green up with rain and heat as spring comes along. So, water browning grass deeply in most instances and it should turn green again during its season. Wait and see how it recovers before throwing more water at the problem. Some browning, especially in circles, actually can indicate fungal growth, and adding more water will make the situation worse.

Q. When do you stop watering your lawn? This will depend on where you live and your local climate. But in general, most regions stop watering their lawns between October and December.

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