How Long Should I Water My Lawn?

Most lawns need about 1 inch of water per week throughout the growing season, which is best delivered in two to three deep watering sessions rather than light daily watering. For most sprinkler systems, this means watering for 20–30 minutes per session, two or three times per week, depending on your climate and soil type.

Key watering guidelines:

• Aim for a total of 1- 1.5 inches of water per week from rain and irrigation.  During extreme heat you may need to target the upper end of this range or even supplement this amount with an additional day or days of irrigation.
• Session duration: Usually 20–30 minutes but test your sprinkler output with an empty tuna can, plastic storage container or rain gauge to be sure.  If puddling occurs, note the amount of run time and don’t exceed this amount in one watering.
• Frequency: Water your lawn 2–3 times a week; sandy soils may need three, clay soils may need only once or twice.
• Best time: Early morning (the first three hours of light) is ideal to minimize evaporation and disease.
• Do not water in small amounts daily. Frequent shallow watering causes weak, shallow roots and will lead to a reduction in drought tolerance.
• Adjust based on soil type; sandy soil will need to be watered more frequently and in smaller amounts to keep moisture from running through the rootzone.  If you find you have significant sand, apply organic material or use a fertilizer that has organic material such as compost or biochar regularly to slowly increase the water holding capacity of your soil.  Clay soils will need to be watered longer and less frequently (but avoid puddling) and loamy soil should follow these guidelines closely.  Just as with the sandy soil the clay and loam soils will also benefit from organic additions.
• Why puddling may occur and how to handle it:  Puddling or runoff may occur due to high levels of clay, from compaction, due to sloped lawns, or even from very high sprinkler output.  The total amount of water needed is still the same, so you may need to split your run times.  What does this mean?  If you notice puddling after 15 minutes but need to run the sprinklers for 30 minutes to deliver enough water, then run the sprinklers twice during that day for 15 minutes each spread across the day.

Sprinkler heads matter, here are some very general guidelines:

• Spray heads: 7-12 minutes per session.

• Rotor, rotator, or rotary heads: 25–35 minutes per session.

How to Check If You're Watering Enough:

• Place shallow containers (like tuna cans) around your yard; run sprinklers and measure how long it takes to fill to 1/3 or 1/2 inch (your per-session target).
• Soil should be moist at 6 inches deep; you can easily check this with a soil probe.
  

• Grass should spring back after stepping on it; if you see footprints that don’t rebound, it may need more water.
• When looking at the color, if you see areas that are taking on a dark green-blue to gray color, this may be an indication of drought stress.
• On mornings with dew, you may see areas that don’t have dew, these areas will certainly need supplemental irrigation.

Adjust for rain, temperature, soil, and grass type as needed. More heat or sandy soils require more frequent watering; cool weather or clay soils require less.