To determine how long you need to water to get one inch, place a plastic container in your yard and set a timer. On average, it will take 30 minutes to get a half inch of water. So, 20 minutes, three times per week will give a lawn about an inch of water. This formula works best with healthy, well-cultivated soil.
For conventional sprayheads, precipitation rates typically range from 1.3 inches to 2 inches per hour. For gear drive rotors, precipitation rates typically range from 0.4 inch to 1 inch per hour. For rotary nozzles, precipitation rates typically range from 0.4 inch to 0.6 inch per hour.
The answer is that it usually takes up to 30 minutes to get a half inch of water. Watering 3 times per week equals to an inch of water on a lawn. Plants can be watered 1 to 2 times a week in seasons where there is a higher chance of rainfall and less evaporation.
At different pressures, the sprinkler head and nozzle will consume different amounts of water. For example, at 35 pounds per square inch (PSI) the 5000 Series Rotor using the 3.0 nozzle will use 3.11 gallons per minute (GPM). If your home's water capacity was 10 GPM, you could place 3 heads per zone.
You can operate 2 or 3 sprinklers at one time with 'Y's and extra hoses, depending on your water pressure. To run more than one sprinkler off the same faucet, attach a 'Y' to your faucet and run a hose to each sprinkler.
Nothing should be in that area between the bottom of the sprinkler heads and the imaginary horizontal plane parallel to the ceiling that is 18 inches below. This is done to allow an even and unobstructed spray pattern from the sprinklers when triggered to extinguish the fire.
The average system uses approximately 15-16 gallons per minute, per station.
If your sprinkler output is 1½ inches per week, your sprinklers should run for only ⅓ hour or 20 minutes that week (½ divided by 1½). On a twice-weekly watering schedule, run your sprinklers 10 minutes each time.
One inch of water or rain is equivalent to 623 gallons per 1,000 square feet.
For vegetables in the summer, we recommend applying about 1 inch of water over the surface area of the garden bed per week. That is equivalent to 0.623 gallons per sq ft. Using that rate, a 32 sq ft bed requires 20 gallons of water per week.
Water Wisely
Many of us water too often and too long. Most lawns need to be watered no more than three days a week in the spring as well as in the summer and two days a week in the fall. This watering schedule is recommended under normal water supply conditions.
Watering with a typical sprinkler using a standard 5/8" garden hose for one hour uses about 1,020 gallons of water; if you water three times per week, that's about 12,240 gallons per month.
Sprinklers generally cover up wider ground and spread out water at a slow yet steady pace, which makes all the soil moisturized evenly and soaked underground. A watering hose takes time to cover space and can clutter the soil if there's too much water.
You should run your sprinkler system for as long as it takes to apply a half inch of water to your lawn. You will need to water for at least 10 minutes per week for most systems. Measure your sprinkler system's output to ensure you're not using too much water or underwatering.
To calculate the amount of water you use, multiply the width times the length of your yard in feet to get the number of square feet of area. Then multiply that figure by 0.623 to come up with the number of gallons used (or use our calculator below).
A common rule that is followed for obstructions within 18 inches of the sprinkler deflector is the “three times rule”. This requires sprinklers to be positioned away from obstructions a minimum or three times the maximum dimension of the obstruction.
1.3 lays out the “Three Times Rule” which states that unless specific requirements are met that “sprinklers shall be positioned away from obstructions a minimum distance of three times the maximum dimensions of the obstruction”, up to a maximum of 24 inches (0.6096 m) though the “maximum clear distance does not apply ...
Sprinklers should be set to run for about 30 to 35 minutes at a time twice a week. Your goal is at least 1″ of water a week for your lawn. When it's hot and dry, double the water times while still trying to water just 2 or 3 days a week.
The rules vary by system type. Pipe-schedule systems and hydraulically calculated systems with a density at or over 0.25 gallons per minute per square foot have a 12-foot (3.7 meters) maximum distance between sprinklers. Hydraulically calculated systems with less density have the standard 15-foot (4.6-meter) maximum.
Irrigation lines are typically installed at a depth of 10” (to the top of the pipe) to prevent a standard 8\" shovel blade from reaching the lines. A 12” depth would be best. This is for residential installations, not commercial. The mainline (pressurized line) should be between 12” to 18” deep.