Garden hose filters are sold as one product category and are really four, each doing a different job, and buying the wrong one is why so many of them disappoint. The four are sediment cartridges, carbon cartridges, deionizing cartridges and drinking water rated units, and the right choice follows entirely from what you intend to do with the water.
Sediment, for irrigation and equipment
The cheapest and the most useful. A sediment cartridge catches sand, rust flakes and pipe debris, and its real value is protecting things with small passages: drip emitters, micro sprinklers, misting lines, pressure washer pumps and the fine nozzles on garden sprayers. All of those block on particles too small to see, and clearing a drip line is far more work than changing a cartridge. If you are irrigating from a well or from older pipework, this is the one to fit and the interval will be short.
Carbon, for chlorine and living things
Carbon takes out chlorine and chloramine and their taste, which matters wherever the water goes to something alive. Filling a pond or an aquarium straight from a chlorinated hose is harmful to fish and to the biological filter, livestock troughs benefit, and sensitive plants and hydroponic systems do too. Contact time in a small housing is short, so flow must be modest for it to work properly, and the cartridge is consumed by the chlorine load rather than by dirt. Our replacement cartridge guide covers matching sizes.
Deionizing, for spot free rinsing
This is the only type that addresses water spots, and it does so by removing the dissolved minerals entirely using ion exchange resin, which no sediment or carbon cartridge can do. It is what car detailers and window cleaners use for a final rinse that dries without marks. Two honest warnings: the resin is consumed quickly, especially on hard water, so the running cost is significant, and the cartridges are considerably more expensive than the other types. A conductivity meter tells you when the resin is spent.
Drinking water rated, for camping and RVs
A separate category defined by the materials rather than the media. These use hoses and housings certified as safe for potable water, since an ordinary garden hose leaches from its lining and its fittings and should not be used for drinking water regardless of what filter is attached. They typically combine sediment and carbon. Note what they do not do: none of them disinfect, so water from a doubtful source still needs treatment. And no outdoor housing should be left full of water over winter, since freezing splits it.
Questions people ask about garden hose filters
Which hose filter stops water spots?
Only a deionizing cartridge, which removes the dissolved minerals by ion exchange. Sediment and carbon cartridges cannot touch them.
What should I fit before drip irrigation?
A sediment cartridge. Drip emitters and micro sprinklers block on particles too small to see, and clearing a line is far more work than a cartridge change.
Can I fill a pond straight from the hose?
Not safely on a chlorinated supply. A carbon cartridge removes chlorine and chloramine, which harm fish and the pond's biological filter.
Is a garden hose safe for drinking water?
No. Ordinary hoses and fittings leach into the water. Use a hose and housing specifically certified as potable water safe.