How to Change a Filter on a Water Filtration System

Water filters come in all shapes and sizes. Here's how to change an under-sink type. Change your water filter at least every six months.

Difficulty:

Moderately Easy

Instructions

Things You'll Need

• Bath Towels
• Replacement Water Filters Cartridge
• Silicone Lubricants
• Sump Wrenches

1. Close the cold-water water valve that feeds the filter.

2. Release any pressure in the line by turning on the cold- and hot-water faucets; leave them open. Some filter models also have a vent valve on top of the filter that you press to release pressure.

3. Turn the sump clockwise using the sump wrench that came with the filter to remove it. Be careful: It's most likely full of water.

4. Locate and set aside the O-ring seal.

5. Remove and throw away the used filter cartridge.

6. Clean the inside of the sump with hot, soapy water and rinse it very well. (Remember that you turned the water off at the sink you're working on.)

7. Insert the new filter cartridge in the sump. Check the label on the filter - some are designed to be installed in a specific direction.

8. Grease the O-ring with clean silicone lubricant. Be sure that it seats completely in its groove.

9. Line up the sump with the filter head and screw it back on.

10. Tighten the sump by turning it counterclockwise.

11. Repeat these steps for the other sump if you have more than one on the filter unit.

12. Stick the reminder label that typically comes with the filter onto the sump.

13. Open the water valve slowly and fill the filter. If you have a vent valve, hold it down while the filter is filling to keep air out of the line.

14. Turn off the faucets and check the unit for leaks.

15. Run the water for 5 minutes to clear out carbon particles that have settled in the cartridge.

Tips & Warnings

• The sump is the tall, cup-shaped, reservoir part of the filter.

• If you don't have a sump wrench, you can use adjustable pliers, but wrap a soft rag around the sump first.

• If the sump won't screw back on, turn the filter around - you may have it in upside down.

• If the unit leaks after reassembly, turn the faucets back on, close the water valve, take the pieces apart, and remove the sump again. The culprit is usually the O-ring slipping out of its groove.

• Keep a bath towel handy - just in case.

• Be very careful not to cross-thread or overtighten the sump(s) or you may have a flood on your hands.