Inline hose filters are simple and most of the trouble with them is mechanical rather than anything to do with water. Getting the fittings right and hanging the body somewhere sensible is nearly the whole job, and it is what separates a filter that works through a season from one that cracks at a joint in the first month.
Threads and couplers
Domestic outdoor taps and hoses use a common hose thread, and most inline filters are supplied with that thread at both ends so the body sits between tap and hose. Check whether the ends are male, female or a mix before ordering, since that decides which adapters you need. Quick connect systems are the usual complication: a filter with fixed threads needs a coupler at each end to join one, and each junction is another place to leak. Buy a spare washer set at the same time.
Mount it at the tap
The most common failure is connecting the filter part way along a hose so the body lies on the ground, gets dragged across paving, stood on and eventually cracks at a fitting. Mount it at the tap end where the tap carries the weight and the joints are not under load. If it has to sit at the far end to protect a specific appliance, support it on something rather than letting it hang. Keep it out of direct sun, which embrittles plastic bodies over a season.
Flow, and choosing a rating that suits
Every cartridge restricts flow, and a small one at hose flow restricts noticeably. Choose a coarser rating than instinct suggests, because a fine element on a garden line blocks quickly and turns a five minute fill into a long wait for very little benefit. If flow matters, prefer a body that takes a larger standard cartridge over the smallest sealed inline unit. A sharp drop in flow during use means the cartridge is loading and is due for replacement or cleaning.
Winter and replacement
Water left inside will freeze and split the body, so drain it at the end of the season and store it dry and out of sunlight. Most inline hose units are sealed and replaced whole rather than recartridged, so note when it went into service and replace on the manufacturer's stated volume or duration. And keep its limits in mind: it will not soften water, will not stop car washing spots and is not certified to make water drinkable. Our inline filter guide compares potable rated units with garden versions.
Questions people ask about inline garden hose filter
Where should the filter be mounted?
At the tap end, where the tap carries the weight. A filter lying mid hose gets dragged, stood on and cracked.
What rating should I choose?
Coarser than instinct suggests. A fine element at hose flow blocks quickly and turns a short fill into a long wait.
Do I need adapters?
Check whether the filter's ends are male, female or mixed, and expect couplers if you use a quick connect system.
What about winter?
Drain it and store it dry. Water left inside will freeze and split the body.