Complete Guide to Choosing and Installing a Check Valve for Your Kitchen Sink
If you've ever experienced clogged drains, foul odors, or contaminated water coming from your kitchen sink, a check valve may be the solution. Check valves are simple but important devices that prevent backflow and keep your clean water supply protected.
You'll learn the different types of check valves, why they're critical for kitchen plumbing, how to select the right one, and step-by-step installation instructions.
Why Do You Need a Check Valve Under Your Kitchen Sink?
Check valves are required under most kitchen sinks because they prevent backflow contamination. Backflow occurs when water flows in the opposite direction from its normal flow. This can allow dirty water from your sink to flow backwards into your home's clean water supply.
Types of Backflow
There are two main types of backflow:
- Backpressure backflow - when backward pressure builds up and is greater than the supply pressure
- Backsiphonage backflow - when a vacuum or negative pressure sucks water backwards through pipes
Backflow can allow chemical, biological and physical contaminants from entering your potable water system. Installing a check valve creates a physical barrier to stop backflow.
Choosing the Right Check Valve
Several factors go into choosing the right check valve for your kitchen sink:
- Pipe size - Match the check valve to the diameter of your supply lines
- Flow rate - Select a valve rated for the sink's expected water flow rate
- Pressure - Consider minimum and maximum pressure ratings
- Fluids - Determine if handling hot water, chemicals, etc.
- Installation - Pick a compact, easy-to-install model
Types of Check Valves
There are many check valve designs, each with pros and cons:
Swing Check Valves
A swing check uses a hinged disc to open and close. Simple, reliable, and inexpensive.
Spring Check Valves
A spring keeps the valve sealed. Good for low pressure and preventing slamming.
Ball Check Valves
A ball lifts off a seat to allow flow. Handles high temps and pressure with little maintenance.
Stop Check Valves
A plunger mechanically seals flow. No backflow leakage but higher maintenance.
Lift Check Valves
Uses a lifting ball or disc for low cracking pressure. Good for low flow velocity.
Tilting Disk Check Valves
Angled discs seal tightly. Good for high pressure and temperature.
Duckbill Check Valves
A duckbill-shaped rubber seal allows forward flow but blocks backflow. Simple, flexible option.
Diaphragm Check Valves
Uses a flexible membrane. Allows higher flow rates with lower pressure loss.
How to Install a Check Valve Under a Kitchen Sink
Getting Started
Before installing a check valve, you'll need to turn off the water supply lines and drain the pipes. Have your check valve, connectors, and tools ready.
Installation Steps
Here are the basic installation steps:
- Disconnect supply lines and remove existing connections.
- Cut into the supply line at the desired location to insert the check valve.
- Place the check valve in the supply line, ensuring the flow arrow points in the correct direction.
- Use connectors to secure the check valve to the supply line openings.
- Reconnect the supply lines to the faucet.
- Turn on water supply and check for leaks.
Helpful Installation Tips
To make installation easier:
- Allow access for future maintenance.
- Support pipes properly to prevent strain on valves.
- Double check flow direction before turning water on.
Ongoing Check Valve Maintenance
Periodically inspect check valves for proper operation:
- Check for leaks and tighten connections if needed.
- Test for backflow with gauges or food coloring.
- Replace worn gaskets, seals, springs, etc.
- Consider full replacement every 5-10 years.
Frequently Asked Questions
Where exactly should it be installed?
Install the check valve on the supply line below the shut-off valve but above the faucet connections.
How can you test a check valve?
Attach gauges before and after the valve then open faucets to see if pressures differ. Food coloring can also indicate backflow.
What if I have low water pressure?
Choose a check valve with low cracking pressure so it opens easily. Avoid tilting disc and stop check valves.
How long do check valves last?
Approximately 5-10 years depending on water quality and usage before full replacement is needed.
What are signs it needs replacement?
Leaking, difficulty opening, fouled internals, and backflow happening are signs a replacement is needed.
Installing a check valve under your kitchen sink is easy DIY plumbing project that prevents nuisance clogs and contamination hazards. This guide covers the check valve types and installation steps to protect your home's clean water supply.
Following proper selection, installation, and maintenance practices will keep your check valve working properly for years to come. Investing in a quality check valve now avoids expensive plumbing disasters down the road.