What is a Stop and Waste Valve?

A stop and waste valve is a specialized shutoff valve designed specifically for outdoor irrigation systems in areas that experience freezing temperatures. Unlike a standard ball valve or gate valve, a stop and waste valve has a unique feature: an automatic drain port (the "waste") that opens when the valve is closed.

Video: How Stop and Waste Valves Work

How It Works

When you turn the valve handle to the closed position:

Water flow to your irrigation system stops
A small drain port automatically opens
Water downstream of the valve drains out through this port
The drained water flows into surrounding gravel and soil
Your irrigation pipes are left empty and protected from freezing

When you open the valve in spring:

The drain port automatically closes
Water flows normally to your irrigation system
No water leaks from the valve during operation

Stop and Waste Valve Components

Understanding the parts of a stop and waste valve helps you install and maintain it properly:

Key Components

Valve Body: The main housing that contains the ball or gate mechanism
Handle/Lever: Used to open and close the valve (typically 1/4 turn operation)
Waste Port: Small drain hole that automatically opens when valve is closed
Inlet Connection: Connects to your main water supply line
Outlet Connection: Connects to your irrigation system piping
Drain Mechanism: Internal feature that opens/closes the waste port based on valve position

Types Available

Ball Valve Type: Most common, features 1/4 turn operation
Gate Valve Type: Traditional style, requires multiple turns
Brass Construction: Durable and corrosion-resistant
PVC Construction: Lightweight and affordable option

🚰 Shop Stop and Waste Installation Parts at Lowe's — Everything needed for proper installation

Stop & Waste Parts ↗

Why Install Outside Instead of Inside Your Home?

Stop and waste valves are always installed outside, typically near your property's water meter or connection point. Here's why this outdoor installation is critical:

1. The Waste Function Requires Outdoor Installation

It Drains Into the Ground: When you close the valve, water drains out through the waste port and into the surrounding soil. Installing this inside your home would cause flooding in your basement or crawl space every time you shut off your sprinklers!

2. Proper Drainage Depth

Below the Frost Line: The valve must be installed below your area's frost line (the depth at which the ground freezes). This ensures the valve itself doesn't freeze, and the drained water flows away properly. Typical depths:

Northern climates: 24-36+ inches deep
Moderate climates: 18-24 inches deep
Mild winter climates: 12-18 inches deep

3. Drainage to Backflow Preventer

Drains Up to the Backflow Preventer: By being at the start of your irrigation system (at the property line), the stop and waste valve drains all water from your sprinkler pipes, valves, and heads up to the backflow preventer when closed. This protects all your irrigation components from freeze damage. An indoor valve couldn't accomplish this level of protection.

4. Separates Irrigation from Home Plumbing

Independent Control: Installing at the property line creates a clear separation between your home's plumbing and your irrigation system. You can winterize your sprinklers without affecting your home's water supply.

5. Easy Seasonal Access

Convenient Location: A valve box installed over the stop and waste valve provides easy access for seasonal operation without needing to enter your home. Simply remove the valve box lid to turn the system on in spring or off in fall.

Increased Water Flow - Save Money on Zones

Reduced Friction Loss: Installing the stop and waste valve at the property line or meter means your irrigation system starts closer to the water source. This significantly reduces friction loss compared to tapping into water inside your home. With less friction loss, you have more available GPM (gallons per minute) for your sprinkler heads, which means:

Run More Heads Per Zone: Higher available GPM allows you to install more sprinkler heads on each zone
Fewer Total Zones Needed: You may need fewer zones to cover your entire property
Less Equipment Required: Fewer zones means fewer valves, less wire, and fewer controller terminals
Significant Cost Savings: This can save hundreds of dollars in installation costs

Understanding Friction Loss

Friction loss is the reduction in water pressure that occurs as water travels through pipes. The longer the pipe run, the more pressure you lose. When you tap into your home's water supply inside your house, you're adding 50-100+ feet of pipe distance before water even reaches your irrigation system.

Real-World Example

Consider a typical scenario:

Tapping inside your home: Water travels 75 feet through 3/4" pipe before reaching the property line, losing 3-5 PSI. At 50 PSI, you might only have 12 GPM available for irrigation.
Installing at property line: Water goes directly from the meter to your irrigation system, maintaining 53-55 PSI. You now have 15-16 GPM available.

That extra 3-4 GPM means you can run 1-4 additional standard spray heads per zone. Over 4-5 zones, this could eliminate the need for an entire zone, saving $200-500 in valves, wire, and components.

Different types of stop and waste valves

Why Does It "Waste" Water?

The term "waste" often confuses homeowners, but it's actually a brilliant design feature that serves a critical purpose:

Not Really Wasteful

Despite the name, stop and waste valves don't waste water in the environmental sense:

Minimal Water Loss: Only the water contained in the irrigation pipes drains out - typically just a few gallons
Infrequent Operation: The drainage only occurs during seasonal shutdown (usually just once per year in fall)
Returns to Groundwater: The drained water goes into the soil, returning to the water table
Prevents Major Waste: Without this feature, frozen pipes would burst, wasting thousands of gallons through leaks

The "Waste" Port Function

The waste port is a small drain hole (typically 1/8" diameter) located on the valve body. Here's how it works:

Valve Open (Summer): Water pressure keeps the waste port sealed shut. No water escapes.
Valve Closed (Winter): The mechanism opens the waste port, allowing downstream water to drain through it.
Drainage Up to Backflow Preventer: Water drains from all irrigation pipes up to the backflow preventer.

Cost vs. Benefit

Consider the economics:

Water Drained: 2-5 gallons per year (pennies in water cost)
Freeze Damage Prevented: Expensive burst pipe repairs
System Longevity: Proper drainage extends the life of your entire irrigation system

Installation Requirements

Critical Installation Factors

1. Depth and Frost Line

The valve must be installed below your local frost line depth. Check with your local building department or irrigation supply store for your area's specific requirement. Common guidelines:

Alaska/Northern Canada: 48-60 inches
Northern US (Minnesota, Montana, Maine): 36-48 inches
Midwest (Iowa, Illinois, Ohio): 30-36 inches
Mid-Atlantic (Virginia, Maryland): 24-30 inches
Pacific Northwest (Oregon, Utah, Washington): 18-24 inches
Southern States: 12-18 inches (if needed at all)

2. Gravel Base Requirement

A proper gravel base is essential for drainage:

Use 3/4" drain rock or pea gravel
Create a base 12-18 inches deep beneath and around the valve
Gravel should extend 6 inches beyond the valve in all directions
This allows drained water to disperse into surrounding soil

3. Access Box Installation

Install a valve box (also called a valve cover or irrigation box) for easy access:

Use a box sized appropriately for your valve (usually 6" or 12" diameter)
Position so the top is flush with or slightly above ground level
This prevents grass from covering the access point
Makes spring startup and fall winterization much easier

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