How to Replace a Sprinkler Stop-and-Waste Valve


Replacing a faulty or leaking sprinkler stop-and-waste valve is an important maintenance task for any irrigation system. A stop-and-waste valve is installed underground and acts as a shut-off for the sprinkler system. When this valve fails, it can lead to major water waste, flooding, and damage if not addressed promptly.

While a seemingly straightforward DIY project, replacing a sprinkler valve does require proper planning, patience, and some specialized tools. With the right approach, however, this repair can be accomplished successfully even by homeowners with minimal plumbing experience.

In this comprehensive guide, we will walk through the entire process of replacing a sprinkler stop-and-waste valve step-by-step. We will cover the key preparations, materials, tools, safety tips, steps for locating, accessing and removing the old valve, installing the new valve, testing for leaks, and restoring the area afterwards.

Follow along carefully, take your time, and refer to this guide anytime you need to replace a faulty sprinkler valve in your system. Let’s get started!

Steps to Replace a Sprinkler Stop-and-Waste Valve

1. Turn Off Water Supply and Drain the System

The first critical step is to turn off the main water supply to the sprinkler system and drain any residual water from the pipes. This prevents water from spraying or leaking when you remove the valve.

Locate the main shut-off valve for the sprinkler system, usually near the water meter or irrigation control valves. Turn the valve clockwise to shut off the water.

Next, go to the lowest sprinkler head or drain valve on the system and remove the cap. Turn the sprinkler system controller on momentarily to allow all remaining water to drain out of the pipes.

2. Gather Necessary Materials and Tools

Before digging, make sure you have all the right materials and tools on hand for a smooth valve replacement process:

  • New sprinkler valve – Match the flow rate (GPM), size, and type of the old valve. Anti-siphon valves are common.
  • Valve box and riser – For underground access to the valve.
  • Shovel – For digging to access the valve.
  • Hose bib valve – For flushing debris after install.
  • PVC primer & cement – For connecting new valve.
  • PVC cutters – For cutting pipes.
  • Adjustable wrench – For tightening fittings.
  • Channel lock pliers – For loosening stuck fittings.
  • screwdrivers – Flat and Philips types.
  • Rags & bucket – For cleaning fittings.
  • Teflon tape – For sealing threaded fittings.
  • Work gloves – For hand protection.
  • Goggles – For eye protection from debris.
  • Knee pads – For comfort while digging.

3. Locate the Sprinkler Valve

The old leaking valve must be located before it can be replaced. Refer to original irrigation plans if available. Otherwise, trace the water lines back from the affected sprinkler heads to find the valve.

Use flags or spray paint to mark the approximate location above ground. Stop-and-waste valves are commonly found 6 to 12 inches below ground beside hardscapes or in planted areas.

Use a shovel to carefully dig a rectangular exploratory hole where you estimate the valve is located. Dig towards the affected sprinkler heads. Expose PVC pipes and follow them to the valve.

4. Access the Valve Box and Valve

Once the valve is located, widen the hole as needed to fully expose the valve box and riser housing the valve assembly. Remove soil and debris from the valve box to gain access.

If present, unscrew the riser securing screws or nuts to detach the top cap for access inside. Remove any rocks or debris surrounding the valve.

Use channel lock pliers to loosen and remove the lock nut on thevalve inlet and outlet pipes. This allows the valve to be freed from the pipes when ready.

5. Remove the Old Valve

With the old valve now accessible and detached from the pipes, it can be removed.

First, disconnect the control wires. Label wires with masking tape to identify for re-connection later.

Unscrew the bonnet or solenoid on electric valves. Remove any screws securing the valve in place.

Twist and pull the valve body upward to remove it from the PVC pipe fittings. Place the old valve aside to return with for sizing the new one.

Inspect the valve box, pipes, and fittings for any cracks or additional leaks needing repair before installing the new valve.

6. Prepare the New Valve

It’s recommended to replace the old valve with the same make and model if possible. If substituting a different valve, ensure it matches the:

  • Flow rate (GPM)
  • Pipe size
  • Type (anti-siphon, electric, manual, etc)

Wrap male pipe threads with 2-3 layers of Teflon tape in a clockwise direction. This seals the joint. Avoid over-tightening.

Apply PVC primer to the cut ends of the pipe where the valve will attach. Then apply a coat of PVC cement. Work quickly while cement is wet.

Position the new valve aligning with the inlet and outlet pipes. The flow arrow should point away from the water source.

7. Install the New Valve

Carefully insert the new valve into the prepared PVC pipe connections while they are still wet with cement.

Wiggle the valve gently to fully seat it within the slip joints. Align it straight. Allow cement drying time before fully tightening fittings.

Reattach the lock nuts securing the valve to the inlet and outlet pipes. Hand tighten only. Do not overtighten.

Reconnect control wires to the new valve solenoid or bonnet as labelled when removed from old valve.

Secure the new valve within the valve box using any existing screws or brackets if needed.

8. Test for Leaks

The new valve is installed but it must be checked for leaks before completing the project.

Turn the main water supply back on slowly. Maintain access to the shut-off in case leaks occur.

Power up the sprinkler system temporarily. Observe the new valve and all connections for any drips or water spraying indicating leaks.

If leaks occur, turn off the water immediately. Tighten fittings or re-cement joints as needed to resolve leaks before retesting.

9. Flush Debris and Test System

With no leaks present, flush debris from the pipes using a hose bib installed after the new valve.

Turn on the sprinkler system in manual mode. Operate each zone to verify proper water flow. Check sprinkler head function and coverage as well.

Finally, run the system in automatic mode according to its watering schedule. Monitor the new valve and system for proper automated operation.

10. Restore the Sprinkler Valve Area

Once operation is confirmed, the new valve and piping can be restored underground:

  • Fill the valve box halfway with dirt.
  • Place the riser over the valve and secure with screws/nuts.
  • Fill remaining space around pipes with soil, compacting lightly.
  • Replace any sod, plants or materials displaced by digging.

The sprinkler valve replacement is now complete! Proper maintenance like winterizing can help maximize the lifespan of the new valve. But following this guide when needed will allow you to safely replace a faulty sprinkler stop-and-waste valve again in the future.

FAQs About Replacing Sprinkler Valves

What are the signs that a sprinkler valve needs to be replaced?

Common signs include the valve leaking constantly, valves not opening fully, valves failing to close fully, reduced water flow, or valves not responding to automatic commands. Corroded, cracked, or unstable valves should also be replaced.

Can I replace a sprinkler valve myself or do I need a professional?

With proper planning and care, most homeowners can replace standard sprinkler valves on their own by following the steps here. But for complex systems or tricky site conditions, hiring an irrigation specialist may be advisable.

How do I find the correct replacement valve for my system?

Check the existing valve for its pipe size, flow rate (GPM), type (anti-siphon, electric, etc), and features. Match those specifications as closely as possible when purchasing a new replacement valve.

What is the average cost to replace a sprinkler valve?

The supplies may cost $25 to $150 depending on valve type and features. Hiring a pro averages $175 for labor. Doing it yourself saves significant cost.

Should I replace all my old valves or just the failed ones?

Replacing all valves at once can minimize future repairs, but isn’t always cost-effective. Focus first on replacing any visibly faulty valves. Eventually phase in new valves over time.

What precautions should I take when replacing a sprinkler valve?

Key precautions include turning off water supply, draining pipes, digging carefully, shutting off power to electric valves, avoiding PVC glue over-tightening, rechecking for leaks, and flushing debris from the system after.

How long does it take to replace a sprinkler valve?

Once located, an experienced DIYer can replace a standard sprinkler valve in 2 to 3 hours. Professional replacement takes 1 to 2 hours. Drying time for PVC glue adds to total time.

Should I replace my old valve box and riser too?

The valve box and riser housing typically last many years. But if cracked or badly deteriorated, replacing them when the new valve is installed will upgrade the access and protection.

Can I convert an old manual valve to an automatic remote control valve?

Yes, standard electric activation kits are available to convert most manual stop-and-waste valves to wired electric remote control. This allows automated operation.


Replacing a failed sprinkler stop-and-waste valve is an essential irrigation system repair. With proper materials, preparations, and following the step-by-step process, even homeowners can successfully replace a leaking or defective valve. Pay close attention to positioning, leak testing, flushing debris, and restoring the valve area to ensure smooth system operation after the repair is complete. Referring to this guide, the process can be repeated whenever a sprinkler valve replacement is needed.