Designing Irrigation Systems to Save Water
The design of an irrigation system can significantly impacts water efficiency. For example, ever seen a perfectly green lawn with a few brown spots? An efficient irrigation system will be designed to apply water evenly.
Start by reading about Efficient Irrigation Services and Products (pdf).
Then ask yourself or your designer these questions
- Is the contractor certified? Learn about Hiring a Certified Irrigation Contractor. Contractors who take the time to get various certifications are typically more educated and professional in their system design and installation (though that is not always a guarantee).
- Does the design of the irrigation system group plants by watering needs? A lot of water can be wasted by grouping plants with different watering needs into one zone. Doing this results in some areas being over or under-watered. The following should never be on a single zone:
- Shrub and lawn
- Sun and shade
- Spray heads, rotors and drip irrigation
- Is there a pressure problem? Incorrect pressure (high or low) will cause wet and dry areas. It can also cause water to drift and blow away from the irrigated area.
- Is your pressure high or low?
- Does the sprinkler head or drip type selected account for that?
- If you have high pressure will the system have pressure regulation?
- Will the system have a Rain Switch? In the Puget Sound area Rain Switches are critically important. Never buy a system without one.
- Over-spraying. Does the design ensure that water will not be over-spraying onto sidewalks, drives or patios? Gross overspray is typical of a bad design.
- Will the system be controlled by weather or soil moisture sensors? These are called SMART controllers and are fast becoming the standard for efficient control of irrigation systems.
- Are the shrub areas being watered with drip? Watering shrub areas with overhead sprinklers is very inefficient. Drip should be standard on shrub areas.
- Schedule. Make sure the contractor documents the irrigation run-times for each zone, including days per week, time of day and number of start times. Use the Irrigation Scheduling Chart (pdf) - use as is or make modifications for your site. Irrigation Scheduling Tools (pdf)
- Irrigation Tutorials
- Irrigation Association Best Management Practices (pdf) Design, install and manage turf and landscape irrigation systems
- Washington Backflow Regulations
- Backflow Prevention Alternatives for Home Irrigation Systems (pdf)