I bought a house with an 250+ gallon rain barrel that is exclusively used to pump water to the lawn and garden irrigation system. No human or other animal consumption, no swimming pool or hot tub, no water play, no car washing. Because the water coming from the gutters contains all sorts of impurities, there is a whole-house type water filter between the rain barrel and the pump, mostly to protect the pump and the sprinkler heads. Everything works very well.

The problem is that the previous owner used a 30-micron filter cartridge (pleated) that quickly clogged up, reducing water flow to the point that the sprinklers would no longer rise. A new filter brought everything back to normal.

But, it seems that 30 microns is overkill for this application. I can get a 100 micron filter, but even that seems to be overkill. I just want to remove anything that would clog the pump or sprinkler heads. Sanitation is irrelevant.

Any ideas for a substitute cartridge better suited to irrigation applications?

It's a common 10 x 4.5 filter with a 1-inch center hole.

UPDATE: I didn't say it explicitly, but all I have against continuing to use the 30 micron filters is the expense. But, I have a filter cleaning kit I bought for our spa filter, and I'm going to try that. Also, I've since learned that there are lots of contaminants in roof runoff that I don't want on my garden edibles, and, while even a simple 30 micron filter won't eliminate all of them, going to a coarser filter seems counterproductive. I'll post here whether filter cleaning was successful. (Successful means that the water flow is restored to what it is with a new filter, or nearly so.)

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    Find out what the pump can take. The filter is to remove particles that can damage the pump. Filters cheap, pumps expensive.
    – crip659
    Jul 8, 2023 at 21:51

2 Answers 2


Some filter setups, eg for swimming pools, let you easily "backwash" the filter, running water backward through it to flush the material it caught to a place where it won't clog things. You can do the same manually by dismounting the filter and running water through it the other way, or dismounting the filter medium and washing it in a sink.


I'd want to see what could be done with something like a big sand filter (easily backwashed) on the way INTO the tank, without backing up too much and losing too much water. However....

For drip irrigation, a 200-mesh filter (74 micron) is generally considered adequate by most manufacturers. This one suggests 150 mesh as adequate for this product.

Sprinklers don't even need that much, a far as I recall. Check the documentation for your specific sprinker types. This site suggests 30 mesh (533 micron) for sprinkler heads, 60 mesh-100 mesh (254-152 micron) for irrigation valves and gear-drive sprinklers.

No affiliation with either site, just looking for irrigation filtration suggestions from suppliers.

I will say that the type of filter that swirls the water around a screen element and dumps the crud down where you can blow it out (and clean the screen) by opening a valve for a few seconds is far more convenient (and less expensive to maintain) than a cartridge filter where you have to take it apart and discard the element, when dealing with water with a lot of crud in it.

Given your update mentioning concerns with other roof runoff contaminants, you might want to insert e.g. a reed-bed filter or similar (plenty of info available from permaculture resources, for free, even) between the roof and the storage. That might require moving the storage downhill or underground (the other flavor of downhill, when a hill to go down isn't actually handy.)

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