Why Water Seeps From Sprinkler Heads After Shutoff
You shut off the sprinklers, but water keeps trickling out of the lowest heads for a while, leaving a soggy, eroded spot. This common issue is called low head drainage, and while it looks like a leak, it has a specific cause and fix. Here's what's happening.
What is low head drainage?
When a zone shuts off, the water still sitting in the pipes drains downhill by gravity and escapes through the lowest sprinkler heads on that line. It's not a valve leak — it's the line emptying itself through the lowest point each time the zone runs. On sloped Inland Empire yards, it's especially common.
Why it's a problem
- It creates soggy, eroded spots around the low heads.
- It wastes the water that drains out after every cycle.
- It can suck dirt into the heads, clogging them over time.
How to stop it
The fix is to install check valves that hold water in the line. You can either:
- Replace the affected low heads with models that have built-in check valves, or
- Add inline check valves on the lateral line.
These let water flow when the zone runs but prevent it from draining back out the low heads when it shuts off.
Distinguish it from a real leak
Low head drainage stops once the line empties (a minute or two after shutoff) and only happens right after a zone runs. Continuous seeping, even between cycles, points to a leaking valve instead. Our irrigation team can install check valves and diagnose the difference.
Frequently asked questions
Why do my sprinkler heads keep leaking after shutoff?
Usually low head drainage — water in the pipes draining out the lowest heads by gravity. Check valves stop it.
Is low head drainage the same as a leak?
Not exactly — it's the line emptying after each run, not a failed component. It still wastes water and is worth fixing with check valves.
Arbol Roble has cared for Inland Empire landscapes since 1997, serving Rancho Cucamonga, Ontario, Fontana, Eastvale, Corona and Riverside. Request a free quote or browse our residential and commercial services.
About the Author
The Arbol Roble team are licensed landscaping and irrigation professionals (CSLB License #1077455) serving Rancho Cucamonga, Ontario, Fontana, Eastvale, Corona, Riverside, and the greater Inland Empire.