If you own an whole house water filter, you will periodically need to replace the filter cartridges. We use a Culligan whole house “Big Blue” water filter to filter out sand and sediment from the well water. It works great, but we find the filters need replacement every 3 – 6 months.
Replacement of the whole house filters is easy, but here is a quick walk through that may help.
Replace the filter cartridge for a whole house water filter
OVERVIEW | Whole House Water Filter Replacement
SUPPLIES LIST | Whole House Water Filter Replacement
TOOLS LIST | Whole House Water Filter Replacement
STEPS | Whole House Water Filter Replacement
- Turn Off Water and Locate the Whole House Water Filter Unit
- Loosen Water Filter Housing and Replace The Water Filter
- Re-assemble the Filter Unit, bleed air and check for leaks
Find your water main shutoff and close the valve. Locate your whole house water filter and the filter housing wrench. If you have a well system, turn off the well power prior to closing the shut off valve to protect the well pump from pumping against a closed system if your main shutoff valve is ahead of the well pressure switch (just turn it off if you’re not sure).
Before opening the water filter housing, drain any upstream water from the system if possible. Most water systems will have a low level drain with a valve that will allow you to empty most of the water from your system prior to opening the filter unit. Our system has a drain just below the filter inlet, making it easy to drain residual upstream water prior to replacing the filter (see below image with white bowl). If you cannot find a drain valve, a basement faucet or other low-level faucet can work to drain the system.
Any water not drained from the system prior to opening the filter will likely empty after you open the filter body. Anticipate the potential for residual upstream water and place a collection basin or similar under the water filter unit prior to opening it.
With the water shut off, the well pump shut off (if you have a well), and the system drained of immediate upstream water, unscrew and open the filter housing and remove the old filter.
Prior to replacing the filter, clean the filter housing. Our filter housing accumulates an impressive collection of sand between filter changes. Prior to placing the new filter, I like to sterilize the housing after cleaning by wiping with a dilute bleach solution and rinsing.
I also will remove, clean and re-lubricate the o-ring at the top of the filter housing. Remove it and pull it through an damp paper towel. Lightly lubricate it with o-ring plumbing silicone prior to replacing it within the groove at the top of the filter housing.
When placing the new filter cartridge, note the filter position within the filter housing and ensure that it is centered and any gaskets on the filter cartridge are aligned properly with the filter housing.
Prior to replacing the filter housing into the filter unit head, clean the groove of the filter until head with a folded damp paper towel or similar.
Re-assemble the filter housing into the filter unit head. Do so by carefully lining up the threads of the filter housing and fit unit head. Once the thread are engaged, hand tighten, then carefully use filter housing wrench to tighten an additional 1/4 to 3/4 turn.
The o-ring seal should seat and be slightly compressed to seal. Over tightening or tightening an un-lubricated o-ring can tear the o-ring and prevent a water tight seal. Buy replacement o-rings and occasionally replace the o-ring with the filter change.
Bleed air from the filter unit by briefly depressing the red bleed button at the top of the filter unit. Finally turn the water back on and carefully check for leaks. I like to use clean paper towel to dry the entire water filter housing, then feel for wetness and evidence of water leaks.