How much to water a lawn and garden, and when a sprinkler system makes sense

Updated November 10, 2026 · KeystoneProGuide editorial team

How much water does a Pennsylvania yard need?

Less than many sprinklers deliver. The EPA's WaterSense program says a landscape typically requires one inch of water a week, including rainfall, and that the figure varies with where you live, recent weather and the plants. It points homeowners to their Cooperative Extension Service or water utility for local advice. Water matters because outdoor use is large: the EPA says U.S. homes use nearly 8 billion gallons a day outdoors, mainly for landscape irrigation, and that the average household uses more water outdoors than for showering and washing clothes combined.

When should you water, and for how long?

The EPA's advice is practical:

• Not in the middle of the day. The sun evaporates much of the water before it reaches the roots.
• Measure your sprinkler. Put a few empty tuna cans on the lawn and time how long the sprinkler takes to fill them with half an inch of water. Try watering for that long twice a week, watch how the lawn responds, and adjust for the weather.
• Stop when water pools. Pooling means overwatering, which the EPA links to weeds, disease and runoff carrying fertilizer and pesticides into waterways.
• Do not water too often. Frequent watering can drown plants or leave them with shallow roots.
• Break it up on clay or slopes. Where water runs off before it soaks in, the EPA suggests a cycle-and-soak schedule: shorter runs with breaks between them.

What about a lawn in drought?

Penn State Extension says a lawn may not need mowing during drought until growth resumes after rain, and that its seasonal calendar assumes a typical year: in severe drought, some practices should be delayed. The Department of Agriculture adds that mowing higher, removing no more than an inch of blade at a time, can increase a lawn's drought tolerance. A dormant brown lawn in August is not, by itself, a reason to install irrigation.

How should new sod, seed and plants be watered?

New plantings are the exception to "water less". Penn State says:

• Sod: lack of water is the most common cause of failure. Water so it soaks through the sod into the soil beneath, daily if needed, until it has rooted, which may take up to 4 weeks. Keep off it meanwhile. Summer sod needs more frequent watering and takes longer to establish.
• Seed: it must receive regular water, especially until it germinates. This is more likely to happen naturally in fall, one reason Penn State prefers late-summer seeding.
• Fall-planted trees, shrubs and perennials: check weekly and water if dry until winter sets in.

Agree in writing who is responsible for this watering when a landscaper installs a lawn or beds. Seed, sod or overseeding covers the rest of a new lawn's care.

Does an irrigation system make sense?

Sometimes, and the EPA's guidance is mostly about running one well. It says:

• Controllers matter. WaterSense labeled controllers adjust watering to local weather or measure soil moisture, cutting irrigation that plants do not need.
• Pressure matters. High pressure makes sprinklers spray faster than expected and flood parts of the yard; WaterSense labeled spray sprinkler bodies have built-in pressure regulation.
• Use drip where it fits. Microirrigation applies water slowly and directly to the roots of gardens, trees and shrubs.
• Zone by plant type. Similar plants belong in the same zone, allowing for sun, shade and sprinkler type.
• Keep it on the landscape. Aim heads away from sidewalks, driveways and the street.
• Inspect monthly. Look for leaks and broken or clogged heads, and adjust the schedule with the seasons.
• Ask about certification. The EPA suggests an irrigation professional certified by a WaterSense labeled program to design, install, maintain or audit a system.

Plant choice reduces the need in the first place. The Department of Conservation and Natural Resources says native plants, once established, require less maintenance, such as water and soil amendments.

What should you know before trenching for a system?

That the utilities will not mark it later. Pennsylvania One Call says privately owned lines are not marked when a dig request is made, and names sprinkler systems among them, along with drainage pipes, invisible fences and power or gas lines to a pool or grill. Keep a plan of where the lines run, and give it to anyone who digs in the yard afterwards.

What do irrigation systems cost?

National survey figures:

Rain barrels are the low-cost end. The EPA suggests them for collecting roof water for irrigation, and says to check whether any state law limits rainwater collection where you live.

For the year's watering and other tasks in order, see how often and when. For more prices, see the cost guide, and local businesses are on the landscapers directory page.

Sources

1. Outdoors (WaterSense), U.S. Environmental Protection Agency
2. Watering Tips (WaterSense), U.S. Environmental Protection Agency
3. Lawn Establishment, Penn State Extension
4. Lawn Management through the Seasons, Penn State Extension
5. Is Fall for Planting?, Penn State Extension
6. Homeowners and Applicators, Pennsylvania Department of Agriculture
7. Landscaping with Native Plants, Pennsylvania Department of Conservation and Natural Resources
8. Private Lines, Pennsylvania One Call System
9. How Much Does Lawn Care Cost? [2026 Data], Angi
10. How Much Does Landscaping Cost?, HomeAdvisor