Designing a sprinkler system includes sketching the entire watering area, breaking the property into zones related to watering needs, and then picking appropriate sprinkler heads. After choosing heads, you add them to the property sketch.
Before you get started, Don’t forget these critical steps:
- Research local ordinances regarding lawn water usage.
- Check with your city or county offices to determine if you need a permit to install a sprinkler system. Also, find out state and local regulations to see if you can install the sprinkler system yourself or if you need to hire a professional.
- Contact local utility companies to mark out underground lines so you can avoid running piping or putting heads close to electricity, internet, phone, etc.
1. Measure your water supply
We’ve talked in other articles about measuring the water pressure and flow so you know if you have adequate pressure to run a system and how many heads per zone the water flow can support.
How to measure water pressure
Water pressure is critical, as it directly impacts how far the sprinkler heads throw water. A minimum force is needed, and higher water pressure equals greater throw distance. Most systems need between 40 and 80 pounds per square inch (psi).
The best way to check water pressure is to use a pressure gauge from your favorite online retailer or a local hardware store.
Turn off all water outlets (hoses, faucets, shoes) inside and out. Attach the pressure gauge to an outside hose bib and turn on the spigot. Then, read where the needle falls.
Based on the psi reading, you can determine the maximum spray distance and place the heads accordingly.
How to measure the flow rate
The easiest way to measure how much water comes out and how quickly it does so is by conducting what is known as the bucket test.
Place an empty 5-gallon plastic pail beneath the hose spigot, turn on the water at full pressure, and determine how long it takes to fill the bucket.
Gallons per minute (GPM) = 5 gallons / 45 seconds X 60 seconds/minute
2. Measure and sketch the area for the sprinkler system
Gather some graph paper, your favorite pencil, and a tape measure—it’s time to draw!
Go outside and measure the length and width of your property, paying attention to curved or angled sections of the perimeter. Draw it to scale on the graph paper, trying to get it as close to realistic as possible.
It’s helpful to have one inch on the graph paper equal to ten feet in real life. Once you have the perimeter drawn, you’ll need to add all the elements on your property: walkways, driveway, house, sheds, flowerbeds, patios, play areas, etc.
3. Break the property up based on watering needs
This step isn’t creating individual zones just yet. It’s more about splitting your yard into sections based on the landscape and plants based on watering needs. These larger sections are known as hydrozones and should be marked on your sketch.
Hydrozones can be large or small; they must include all areas you’ll water with your sprinkler system. Make sure to include those small strips between the sidewalk and the street and even ground cover plants you want to be watered.
Hydrozones are broken up based on variables including:
- Sunlight exposure. Areas that are heavily shaded—under big trees, next to your house—don’t need as much water as the middle of your lawn, which gets full sun all day.
- Plant type. Your lawn should be a different hydrozone than flowerbeds or even a strip of native plants.
- Soil type. You likely have similar soil across your property, but if there’s a spot where you know it’s a little bit more clay and holds water, or there’s a section full of sand that can’t stay wet no matter what you try, make sure to mark these in different hydrozones.
4. Pick your sprinkler heads
Now that you have the different hydrozones mapped out, it’s time to pick the sprinkler heads to use in each. There are many different brands available to choose from, but you must stick to one manufacturer for the entire system.
When choosing heads, you can pick rotors, fixed spray heads, specialty nozzles, and drip or micro-irrigation sprinkler heads. One spray pattern should end where the next one starts to water an area evenly.
- Rotors spray in a full 360° pattern and can put out a significant amount of water. These are typically used in the middle of your lawn to cover large areas; they can deliver water from a 13 to 30-foot radius. Choose rotor heads based on their radius and the reach they have to cover. Keep the same size rotor head and spray per zone.
- Fixed spray heads come in different angles (typically from 45° to 180°) and have a radius of six to 18 feet. They do not move or rotate and deliver water to a specific area the entire time.
- Specialty nozzles have unique patterns to solve particular landscape problems. They might deliver water to cover a five-foot by 15-foot pavement strip.
- Micro- or drip irrigation sprinklers are helpful for watering ground covers and flower beds or delivering water to trees and shrubs. These small emitters provide water right to the base of a plant, watering the roots.
5. Put the sprinkler system’s layout on paper
After deciding which heads to use, draw out the sprinkler head locations on the sketch and map the spraying patterns. If you use conventional sprinkler heads (whether a smart sprinkler system or not), the spray patterns need to slightly overlap to get good water coverage.
6. Break the hydrozones into small clusters or zones
With all the sprinkler heads on your property sketch, break up the hydrozones into smaller areas that can be set up on a single valve or zone on a controller. This is where you need to use your water flow calculation.
For example, if you’re using a rotor that consumes 3 gallons per minute (GPM) and your home’s water capacity is approximately 10 GPM, you could effectively run three heads per zone. If your heads consume 5 GPM, you could run two heads per zone.
7. Determine miscellaneous parts
Now, you can add the piping between heads, pipe fittings for coerns, valve boxes, etc., to your sketch to build the entire system. Calculate the distance between the different components to determine how much PVC line you need.
8. Finish your plan
Put together a parts list to take to the supply store. Make sure it includes all of the heads, piping, fittings, controller, valves, etc. It’s wise to buy about 10-15% more piping than you think you’ll need to account for mistakes.