Housings are replaced for a few reasons: a cracked sump, a thread that has been over tightened once too often, a leak nothing cures, or an upgrade to a larger body. The goal in most cases is to keep buying the same cartridges, which means matching three dimensions rather than simply ordering something that takes ten inch elements.
Match the cartridge, not the label
Ten inch describes length, and there are two common diameters, so start by measuring the cartridge you intend to keep using: length and outside diameter both. A housing described as taking ten inch cartridges may be built for the other diameter, in which case your existing stock does not fit and, worse, a narrower cartridge in a wider bore lets water pass around it unfiltered rather than failing obviously. Confirm the bore before ordering.
Ports, threads and pipe size
Housings come with different port sizes, and a housing with ports narrower than your pipework throttles the flow it was bought to carry. Match the port size to the pipe, and check the thread type against your existing fittings so the replacement does not require new adapters at each side. If the old housing was undersized for the household's flow, this is the moment to go wider rather than replacing like with like and repeating the problem.
Mounting and clearance
Check the bracket hole spacing against what is already fixed to the wall, since a matching bracket saves redrilling into masonry. Confirm the clearance below the sump is still equal to a cartridge length, which it will be if the housing is the same size and may not be if you have gone longer. And remember a full housing is heavy: the bracket carries it, not the pipework, so upgrade the fixing if you are moving to a larger body.
Fitting the replacement
Isolate and drain first. Use unions or push fittings so the housing can come out again without cutting pipe, which is the difference between a ten minute service and an afternoon. Fit the new o-ring supplied, lubricated with food grade silicone, and hand tighten before a modest pull with the correct wrench. Open slowly, check for leaks by hand and again an hour later once pressure has settled. Our housing replacement guide covers matching housings to existing cartridges.
Questions people ask about 10 water filter housing
Will my existing cartridges fit a new housing?
Only if the bore matches. Ten inch is the length; two diameters are in common use and they are not interchangeable.
What happens if the cartridge is too narrow for the housing?
Water passes around it unfiltered rather than failing obviously, so the filter appears to work while doing nothing.
Does port size matter?
Yes. Ports narrower than your pipework throttle the flow, so match them to the pipe rather than accepting the cheapest option.
Should I replace like with like?
Only if the old housing was correctly sized. If it throttled the house, replacing it with a wider body is the moment to fix that.