Converting a standard sprinkler zone into a hybrid drip system is a cost-effective and water-efficient method for irrigating garden beds, shrubs, and containers. This conversion leverages the existing underground piping and automated zone valve, providing a reliable water source directly to the plants. The primary challenge is adapting the high-pressure, high-flow sprinkler infrastructure to the low-pressure, low-flow requirements of a drip system. Integrating these two technologies requires specific components to manage water pressure and prevent clogs.
Managing Pressure Differences Between Systems
Standard sprinkler systems are designed to operate under high water pressure, typically requiring 40 to 60 pounds per square inch (PSI) for optimal performance. In contrast, drip irrigation emitters and tubing require a much lower operating pressure, usually between 10 and 25 PSI. Applying the full sprinkler line pressure to a drip system will likely cause immediate damage, resulting in blown-off emitters or burst tubing.
Specialized components must be installed to bridge this significant pressure gap and protect the delicate drip components. The conversion assembly must effectively reduce the water pressure entering the drip line to the manufacturer’s recommended range, often targeting 20 or 25 PSI. This pressure regulation ensures that the drip emitters function as intended, delivering water slowly and precisely to the plant root zone.
Essential Conversion Components Checklist
The transition from a sprinkler riser to a functional drip line requires a sequence of three specialized components to manage the flow and pressure. These components form the head assembly that prepares the water for the drip tubing.
The required components are:
- A threaded adapter, which screws directly onto the existing sprinkler riser after the sprinkler head is removed. This adapter typically converts the half-inch pipe thread to a male hose thread, creating a universal connection point.
- A mesh filter, necessary to prevent sediment from blocking the tiny orifices of the drip emitters. This filtration step is paramount, often featuring a fine 150 or 200-mesh screen.
- A pressure regulator, which connects directly after the filter and restricts the water flow to drop the PSI into the acceptable 10 to 25 PSI range.
Connecting the Drip Line to the Sprinkler Zone
Installation begins by shutting off the main water supply and activating the zone to relieve any remaining pressure in the pipes. Locate the specific riser you intend to convert, then use a trowel to excavate the area around the base to expose the connection point. Unscrew the existing sprinkler head or cap from the riser, taking care to prevent soil or debris from falling into the open pipe.
The conversion assembly is built and attached, starting with the threaded adapter screwed onto the exposed riser. The mesh filter is screwed into place next, ensuring the arrow on the filter housing points in the direction of water flow. The pressure regulator is attached to the filter, followed by the tubing adapter, which connects the regulator to the main drip tubing. The main drip tubing is then run from the tubing adapter along the path of the planting bed.
The main drip line, often a half-inch polyethylene tubing, should be laid out following the contours of the area to be watered. Anchor the tubing to the ground using specialized stakes to prevent shifting. Any unused sprinkler risers on the same zone must be capped off with a threaded cap to maintain system pressure for the new drip line.
Testing, Flushing, and Scheduling Adjustments
After installation is complete, the new drip line must be flushed to clear any debris introduced during the conversion process. To flush the line, temporarily remove the end cap or flush valve at the furthest point of the main drip tubing. Slowly turn the water supply back on to the zone, allowing water to flow freely from the open end until it runs clear.
Once the water is clean, turn the water off, replace the end cap or flush valve, and inspect the entire system for leaks under pressure. The final step is adjusting the irrigation controller schedule for the converted zone. Drip systems deliver water much slower than sprinklers, requiring significantly longer, less frequent run times. The new schedule should incorporate deep, soaking cycles, which might involve running the zone for 30 to 60 minutes multiple times a week, ensuring the root zone receives adequate moisture.