A hose water filter is an inline canister with garden hose threads at both ends, screwed between the spigot and the hose. Fitting one takes a minute, but three things decide whether you are happy with it: how much flow it costs you, how the weight is supported at the tap, and whether it survives the winter. All three are avoidable problems.
How it attaches, and the leak everyone gets
Both ends carry a standard garden hose thread, so the filter screws directly onto the spigot and the hose screws onto the filter. Every joint needs the rubber washer that came with it, seated flat in the recess, and hand tight is enough: overtightening deforms the washer and creates the very drip you were trying to stop. Respect the flow arrow on the body, because filters are packed to work in one direction. If the spigot sits low, add a short flexible lead so the canister rests on the ground rather than hanging.
What it costs you in pressure
Any media in the path is a restriction, and outdoor use runs at high flow, so the drop is more noticeable than it would be indoors. A fine sediment cartridge is the worst offender and a coarse carbon the least. Check the manufacturer's rated flow before buying, especially if the hose feeds a sprinkler or a pressure washer that needs a minimum supply. When a filter that was fine last month suddenly leaves the sprinkler weak, it has loaded up with sediment and is telling you to replace it.
Support, mounting and the tap it hangs on
A full canister is heavy, and hanging it directly off a spigot puts a constant bending load on a fitting that was never designed for it. Outdoor faucets have failed inside a wall for exactly this reason. Use a short flexible connector between the spigot and the filter so the weight sits on the ground or on a bracket, and keep the assembly out of the path of anyone mowing or reversing. If the filter has a mounting hole, use it, because a fixed canister is also easier to change.
Choosing the media, and putting it away for winter
Decide the media from what your supply actually carries. Every community water system publishes an annual Consumer Confidence Report and the EPA maintains a finder for it, so the report tells you whether chlorine, chloramine or sediment is the thing to target at the spigot. Then, before the first freeze, disconnect the filter, drain it fully, and store it indoors: water trapped in a canister expands as it freezes and splits the plastic, and a split shows up as a spray the following spring. Our whole house water filter guide covers treating the supply rather than one tap.
Questions people ask about hose water filter
Which way round does a hose water filter go?
Follow the arrow printed on the body, with the marked inlet at the spigot. Media is packed to work in one direction, and reversing it can push loose material into the hose.
Why is my hose filter leaking at the thread?
Usually a missing, twisted or overtightened washer. Fit the supplied rubber washer flat in the recess and tighten by hand, since extra force deforms it and makes the leak worse.
Will a hose filter reduce sprinkler pressure?
Yes, a little when new and considerably once it loads with sediment. Check the rated flow before buying, and treat a sudden pressure drop as a signal to replace the cartridge.
Can I leave the filter connected all year?
Not through a freeze. Trapped water expands and cracks the canister, so disconnect it at the end of the season, drain it completely and store it somewhere above freezing.