Watering by hose and watering by in-ground sprinklers produce different results and use different amounts of water. Hose watering may or may not involve an attachment such as a sprinkler or a sprayer, or may refer to the use of a drip or soaker hose. In-ground sprinklers and garden hose sprinklers alike may deliver a rotating spray of water or a continuous spray from one position.
A sprinkler head may use 15 gallons of water per minute. Most lawns require at least 30 minutes of watering at a time. This means that even for just one sprinkler head, 450 gallons of water are used each time the sprinkler is on for 30 minutes. A hose sprinkler uses between 315 and 930 gallons per every half hour of operation, depending on the size of the hose. If you have five sprinkler stations and run the sprinklers twice a week, you will use 4,500 gallons of water a week. The same length of time watering with a hose will use between 3,150 and 9,300 gallons per week.
Most sprinkler systems are only about 60 percent efficient. Runoff from too much water soaking into the soil at once or hitting trees and sidewalks, along with evaporation reduce the efficiency of sprinklers. That means that of the potential 9,000 gallons of water per week, up to 3,600 gallons will be completely wasted. Hand-held sprinklers reduce the waste because the spray can be directed where it is needed.
There are many drawbacks to sprinkler systems. Aside from the issue of using so much water and the potential water waste, there is also the cost of operating sprinklers. A bill for the use of 9,000 gallons might exceed $200 per month, an expense that many families cannot afford.
It is important to determine if having a green lawn all summer long is important enough to justify the waste and cost that sprinkler systems will cause. Consider watering plants but not watering the grass, or consider watering only during weeks in which no rain falls. Most plants can survive off of 1 or 2 inches of water per week. Install a rain gauge to know when to water.