Under-sink water filters are one of the best ways to filter out impurities and contaminants from your home’s water supply. Installing an under-sink filter provides cleaner, better-tasting water straight from your tap while taking up minimal space under your sink.
While most under-sink water filters come with basic installation instructions, the process can seem complicated if you’ve never done it before. This comprehensive guide will walk you through the entire installation process in detail, with step-by-step instructions, tips, and recommendations for a smooth install.
Benefits of Under-Sink Water Filters
Before jumping into the installation process, let’s first go over some of the main benefits of using an under-sink water filter system:
- Improved Water Quality – Under-sink filters remove up to 99% of major contaminants like lead, chlorine, benzene, sediment, rust, and more. This leaves you with cleaner, better-tasting drinking water.
- Convenience – The filtered water comes straight from your kitchen tap, so you don’t have to buy bottled water or use a pitcher that needs constant refilling.
- Cost Savings – An under-sink filter costs only cents per gallon, while bottled water can cost $1 or more per gallon. The filter also lasts 6-12 months before needing replacement.
- Space Saving – The system installs under your sink out of sight, so it doesn’t take up room on your counters.
- Health Benefits – Cleaner drinking water improves health, skin, hair, and can even aid with weight loss.
Choosing an Under-Sink Water Filter System
With so many under-sink filter options on the market, how do you choose? Here are the most important factors to consider:
Filtration Technology
- Carbon block filters effectively remove chemicals, sediment, metals
- Reverse osmosis filters remove the widest range of contaminants
- UV light systems kill pathogens like bacteria and viruses
Micron Ratings
- 0.5 microns is standard for mechanical filtration; the lower the micron rating, the more particles filtered out
Flow Rate
- Standard flow rate is 0.5 gpm; higher flow rates reduce waiting time at the tap
Filter Capacity
- Standard is 300-500 gallons; higher means fewer filter replacements
Certifications
- NSF certification verifies effectiveness and safety
Warranty
- 5-10 years on parts/systems ensure the filter lasts
Once you select the right under-sink filter for your needs, it’s time to tackle the installation.
Getting Ready for Installation
Before you start installing your under-sink filter system, take the time to fully prepare with the following steps:
Gather Necessary Tools and Materials
You will need:
- Filter system
- Teflon tape
- Crescent wrenches (at least 2)
- Basin wrench
- Utility knife
- Paper towels
- Bucket
- Flashlight
Turn Off Water Supply
Locate the shut-off valve for the cold water line under the sink and turn it clockwise to shut off the water supply. Turn on the faucet to release any pressure and ensure the water is off.
Clear Under-Sink Area
Remove everything from under your sink and set aside to clear space for the filter system. Have your flashlight handy for improved visibility.
Inspect Plumbing
Examine the cold water supply line and main faucet line for leaks, corrosion, or other issues. Replace tubing if necessary.
Review Instructions
Read through all instructions for your specific filter model before you begin. Follow safety notes and verify required parts.
With the prep work complete, it’s time to install your under-sink water filter system.
Step-by-Step Under-Sink Filter Installation
Follow these key steps to properly install your under-sink water filters:
Step 1 – Install Shut-Off Valve
Most filters don’t include their own shut-off valve. Attach a valve to the cold water supply line with Teflon tape so you can easily shut off water to the filter system when needed.
Step 2 – Connect Filter System
Place the filter system in the desired location under the sink. Use a compression fitting to attach the filter inlet to the cold water supply with tubing.
Step 3 – Install Faucet
If your filter came with a separate faucet, install it now per the instructions through an available hole or sprayer nozzle in your sink or countertop.
Step 4 – Connect Tubing to Faucet
Attach tubing from the filter system outlet to the dedicated faucet using the provided hardware, Teflon tape, and wrench.
Step 5 – Flush the System
Turn the water supply back on slowly. Let water run through the filter for 10 minutes to remove air bubbles and carbon dust.
Step 6 – Check for Leaks
Examine the entirety of the system for leaks at connections. Tighten fittings or reapply Teflon tape to stop leaks before finalizing the installation.
And that’s the basics for installing most standard under-counter water filters! Continue reading for more details on connecting specific system components, troubleshooting issues, replacing filters, and properly maintaining your filtration system.
Read More: Guide to Installing a reverse osmosis filter system
Connecting the Filter System Components
Connecting all the tubing between the water line, filter housing, and faucet is key during under-sink filter installation. Here’s a step-by-step look at setting up each component connection:
Cold Water Supply Line
The cold water supply line brings unfiltered water into the filtration system. To connect:
- Insert line into inlet side of filter housing
- Secure metal compression ring
- Tighten ring with wrench
Add Teflon tape to prevent leaks. Avoid connecting to hot water line as heat degrades filtration.
Filter Housing
The filter housing contains the replaceable filter cartridge(s) that handle the actual filtration. Proper housing setup ensures water flows through filters correctly.
- Position housing vertically or horizontally per instructions
- Outlet side connects to filtered water line
- Be sure to insert filters in the correct direction so water flows properly from inlet, through filters, then outlet
Faucet
The faucet dispenses the filtered water with easy access right at your sink. For faucet installation:
- Confirm needed hole size
- Drill hole in chosen location (sink, countertop, etc) if needed
- Insert faucet base through hole
- Secure firmly underneath with provided hardware
- Attach tubing line(s) from filter system to faucet inlet(s)
Faucet placement is very important – make sure it’s easily accessible and the tubing connects and routes properly underneath before securing fully.
Filtered Water Line
The filtered water line carries filtered water from the outlet of the filter housing to the dedicated faucet.
- Cut tubing to the needed length
- Attach tubing securely to outlet port on filter housing
- Route tubing to faucet location
- Attach other end to faucet inlet
Filtered and unfiltered lines must remain totally separate to prevent contamination.
With all the connections secured properly, your under-sink filter system can now effectively filter all cold water from your main supply line through to your new filter tap.
Dealing With Tricky Installations
Some under-sink filter installations prove more challenging than others due to limited space to work, tricky configurations under the sink, or connections to non-standard plumbing. Here are some tips for taking on these tricky installs:
Limited Space
- Look for filter systems with smaller housings that fit compact areas
- Use tubing with pre-attached fittings to eliminate need for tools
Drain Pipe Interference
- Adjust drain pipes with elbow joints to make more room
- Purchase space-saving low-profile filter housing
No Available Faucet Hole
- Use a countertop faucet base if sink has no room
- Install an air gap faucet base in place of existing sprayer nozzle
Apartment/Rental Property
- Choose an easily removable filter housing secured with clamps or quick connects
- Install with compression fittings instead of altering plumbing lines
Difficult Access to Plumbing
- Use many extensions, swivel fittings, and adjustable wrenches
- Reposition and prop up piping to better reach connections
Alternative Water Supply Lines
- Flexible stainless steel supply lines simplify custom plumbing setups
- Use a saddle valve to tap into supply lines without adjustments
With some clever workarounds, you can install an under-sink filter system in practically any home configuration.
Replacing Used Filter Cartridges
Under-sink water filters use replaceable filter cartridges that need regular changing once they reach capacity. Here’s how to safely swap out used filters:
Determine Its Time
Check documentation to see manufacturer-recommended replacement frequency, often every 6-12 months. Track usage with a sticker on your filter housing and replace once capacity is reached.
Turn Off Water & Release Pressure
Locate water supply shut-off valve and turn off the water. Then turn on the filtered water faucet to depressurize lines before opening housing.
Remove Old Filter Cartridge
Open the filter housing by loosening clamps, screws, or collar depending on model. Gently pull old cartridge out of the housing, avoiding any dripping water.
Prepare New Cartridge
First remove any plastic wrapping from new cartridge. Soak carbon filters in water for 5 minutes before installation to purify.
Insert New Cartridge
Place new filter cartridge into housing following arrows or diagrams noting proper direction. Water should flow in through sides of filter, not top or bottom.
Restart System
Reseal filter housing then slowly turn water supply back on. Let water run on full for 10 minutes to flush, checking closely for leaks.
Be sure to reset any filter replacement reminder tracking to monitor when your new cartridge reaches capacity.
Troubleshooting Common Installation Problems
While most under-sink filter installations go smoothly, occasional issues can arise. Here are fixes for the most common problems:
Leaks
- Tighten all fittings with wrench
- Check pipes and tubes for cracks
- Wrap threads with additional Teflon tape
Cloudy Water
- Air bubbles in line; let water run until clear
- Flush new filter thoroughly per instructions
- If cloudiness persists, replace filter cartridge
Reduced Water Pressure
- Filter or pipes clogged – replace cartridge & inspect tubes
- Adjust water supply valve to fully open
- Upgrade to higher flow rate filter if needed
Water Backflow at Faucet
- Improperly installed check valve; verify check valve functioning properly
- Clogged filter – replace cartridge
Bypass Failure
- Remove built-up sediment from bypass valve
- Replace bypass unit if broken
Be sure to fully read through provided instructions and troubleshooting tips before installation. Contact manufacturer customer service for additional assistance if any major issues occur.
Maintaining Your Under-Sink Water Filter
Once installation is complete, some occasional maintenance is required to keep your under-sink filter working properly. Follow these upkeep practices:
Change Filter Cartridges Routinely
Mark calendar reminders to replace spent filters based on usage, capacity, and manufacturer guidelines to maintain filtration.
Periodically Sanitize System
Disinfect interior tubing and housing with dilute bleach solution on occasion to prevent pathogen growth.
Test Water Regularly
Use water testing strips to periodically check filtered water quality, ensure proper performance, and watch for needed cartridge changes.
Clean Exterior Surfaces
Wipe down accessible filter housing, faucet, and other components with soft cloth to keep clean of dust and grime buildup.
Monitor Overall System
Check all tubing, fittings, valves etc. for leaks, cracks, odd smells or other issues indicating problems needing repair.
By properly caring for your under-sink filter with regular maintenance, the system can function reliably for years before significant service is required.
Conclusion
Installing an under-sink water filter in your home provides huge benefits when it comes to your family’s health and drinking water quality. While the installation process may seem complex, having the right tools and following the steps outlined in this guide will set you up for success.
The most important points to remember are:
- Thoroughly prepare your under-sink area in advance
- Carefully follow instructions for YOUR specific filter model
- Take your time making secure tubing connections
- Flush the system well post-installation before first use
Additionally, don’t hesitate to contact the manufacturer, plumber, or home improvement expert for advice if any issues pop up.