Best Sediment Filter for Well Water (Cartridge, Spin-Down & Backwashing Compared)

People call me asking what type of sediment filter they need for their house, and there are only three answers: a Big Blue cartridge filter, a Rusco spin-down screen, or a backwashing sediment tank. Most well homes need the first one. A well that pumps sand gets the second one added on, last in line. A few wells put out so much dirt that only the tank keeps up. Tap the one that sounds like your water and I will show you why.

Tap your problem. Each photo is the filter I recommend for it.

Fine dirt? A Big Blue cartridge Sand you can see? A Rusco spin-down Plugging fast? A backwashing tank Not sure? Text me a photo

The three types side by side

Each filter catches a different size of dirt. The Big Blue cartridge stops dirt down to 5 microns, the Rusco screen down to about 250 microns, and the Turbidex tank down to 3 to 5 microns with no cartridge to change. Prices are today's prices on our store.

Filter	What it catches	Price	What you do to keep it working	Who it is for
20 inch Big Blue cartridge kit	Fine dirt down to 5 microns	$195; replacement cartridge $55	Change the cartridge every 4 to 6 months, sooner with more dirt	Nearly every well home. Goes ahead of the treatment tanks.
Rusco spin-down filter, 1 inch pipe	Sand and grit you can see (larger than about 250 microns)	$145; no cartridge to buy	Open the valve into a bucket when the bowl fills; the screen rinses and goes back in	Wells that pump sand you can see. Goes last in line.
Backwashing sediment tank (Fleck 2510SXT valve, Turbidex media)	Heavy, constant dirt, down to 3 to 5 microns	$1,895	Nothing by hand. It cleans itself to a drain on a timer.	Wells where a cartridge plugs in days or weeks

The 20 inch Big Blue for most homes

After 32 years with sediment filters, the Big Blue 20 inch is the most reliable one we have found. It traps dirt down to 5 microns without a pressure drop you would notice. The kit is $195 shipped and comes with the Pentair housing, the wall bracket, the wrench and a 5 micron cartridge. It mounts to the wall next to your well tank, right after the tank and before your first treatment tank, so the neutralizer, iron filter or softener never sees the dirt.

Why the 20 and not the 10: the 4x20 gives you greater capacity and does not slow your flow. Pentek's own sheet puts the 20 inch 5 micron cartridge at less than 6 psi of pressure drop at 40 gallons a minute, and the 10 inch cartridge at less than 3 psi at 20 gallons a minute; the housing itself adds about 1 psi at 15 gallons a minute. Both housings take 1 inch pipe. If you are just 1 or 2 people living in the house, you can get away with the 10 inch Big Blue kit at $165. Anyone else, get the 20. Sizes, cartridge types and housings are in the Big Blue housings and cartridges guide.

Why 5 micron: cartridges come in 5, 10, 15, 20 and 25 microns, and we recommend the 5 because it removes extremely small particles, far smaller than a human hair (the EPA puts a hair at about 70 microns). People call me with a 25 micron cartridge in the housing and dirt still coming through; the fix is a 5 micron cartridge. Do not jump to 1 micron either: with a lot of sediment in the water it might clog up pretty quick. The full rundown is in which micron rating to pick.

What it costs to run: every 4 to 6 months or so you shut the water off, relieve the pressure, take the sump off with the wrench and drop in a new cartridge. It depends on how much sediment you have; it could be every 12 months, it could be every other month. A 20 inch replacement cartridge is $55 from us and a 10 inch replacement is $45; locally a 5 micron cartridge runs about $25. People ask if they can wash a cartridge and reuse it. You can do whatever you want to, but we recommend replacing it when it gets dirty.

What it will not do: a sediment cartridge strains particles. It does not touch dissolved iron, manganese, hardness, low pH or bacteria; those need their own equipment, and the Big Blue's job is to protect that equipment.

When to add a Rusco spin-down filter

The Rusco we sell ships with a 60 mesh polyester screen, which means openings of about 250 microns. It catches sand and grit you can see and lets fine dirt straight through. It works by centrifugal force: the water spins, the heavy particles drop into the clear chamber at the bottom where you can see them, and every so often when it builds up you put a bucket underneath, open the valve, and in 2 seconds it flushes itself out. The screen does not have to be replaced; it comes out, rinses and goes back in.

A Rusco is not a replacement for the Big Blue. 250 microns against 5 microns is the whole difference: the screen stops sand, the cartridge stops the fine dirt. If your well pumps sand, run both. The Big Blue sits after the well tank ahead of the treatment tanks, and the Rusco goes last in line to catch anything the tanks let past. One caller asked me about putting 2 or 3 spin-downs in a row with different screens. I told him I would not: the more you put in it, the more you are going to slow your flow down.

Two sizes. The Standard Rusco is 1 inch, rated 1 to 25 gallons a minute, $145. It comes in 1 inch, so 3/4 inch pipe has to reduce down to it. The Large Rusco is 2 inch, rated 18 to 100 gallons a minute, $249, and Rusco says it needs 18 gallons a minute before it spins at all, so it is for 2 inch lines. Everything about the screen choices, flushing and the two sizes is in the spin-down guide.

When a backwashing tank is worth $1,895

A backwashing sediment tank is for the well where Big Blue cartridges plug in days or weeks. Nothing you change by hand keeps up with that much dirt. A caller in September was helping relatives whose well pumps very fine black sand into the appliances:

Caller "We put 2 Big Blue filters on the system, and in a week they were stopped up."

Aidan "That's gonna plug. That's gonna plug too. You need a backwashing sediment filter. If the Big Blue's got clogged that fast, then the Rusco filter's gonna get clogged that fast."

He had asked whether a Rusco would handle it. It would not: a screen fills as fast as a cartridge does. The tank is built like an acid neutralizer with a different media inside, one made for taking sediment out of the water. The one we sell is a 13 by 54 inch tank with 2 cubic feet of Turbidex and a Fleck 2510SXT valve on top, 62 inches tall all together. Turbidex's maker rates it at 3 to 5 microns. On the schedule you set, the valve backwashes: it runs water up through the bed, lifts it, sends the dirt to the drain and goes back to work. There is no cartridge to change. On a well like that caller's, the Big Blue moves to after the tank to catch the fine stuff the tank lets by.

What it needs from your house. A drain: Fleck's manual calls for at least a 1/2 inch drain line, and 3/4 inch when the backwash runs over 7 gallons a minute or the line runs over 20 feet. An outlet that stays on: the valve needs an uninterrupted power supply, so not a switched outlet. Pump flow: Turbidex's sheet asks for 15 to 20 gallons a minute per square foot of tank to backwash, and a 13 inch tank is about 0.92 square feet, which works out to about 14 to 18 gallons a minute (the sheet allows less where local conditions call for it). Know what your well pump delivers before you buy this one. The Turbidex ships in bags and is loaded through the included fill funnel at install; drain tubing is not included. We recommend a licensed plumber for the install and support your plumber by phone at 800-460-5810.

Try the $195 filter first unless the dirt is already winning. A caller in May had a well feeding a 2 acre, 24 zone irrigation system and a pool, turbid after work on the well, and asked me 20 inch Big Blue or the 2.5 cubic foot backwashing system. I told him: if you have heavy, heavy, heavy, heavy sediment, and it is beyond what an inline filter can capture, you would use that type of system. If you have heavy sediment that is already clogging things up, the backwashing sediment filter is the way to go. For $195, I would try the Big Blue first.

Not sure which of the three you need

Text me a photo of your toilet tank

Take the lid off the toilet tank in the bathroom you use most and send me a photo of what is sitting on the bottom, plus how many bathrooms you have. I will tell you which filter, or whether you need one at all.

Text Aidan443-277-2204 Call800-460-5810Aidan

8 AM to 5 PM Eastern, seven days a week. A real person, not a call center.

Where each filter goes in the line

Every sediment filter goes after the well tank. The Big Blue goes right after the tank, before the first treatment tank. The spin-down goes last in line, after the treatment tanks. Nothing goes between the pump and the tank. A filter there hides its own clog from the pressure switch, and the pump keeps running against it until something gives. Water passes through the 5 micron cartridge, the dirt stays in the cartridge, and clean water goes on to the neutralizer or softener and then to the fixtures.

The reason the Big Blue comes first is easiest to see with an acid neutralizer. If you skip the sediment filter and you have a fair amount of sediment, it gets into the neutralizer and works its way to the bottom, and when you add more calcite it compresses that sediment and slows or shuts down your water flow. The why behind the whole order is in how a sediment filter works and where it goes, and the plumbing steps are in how to install a sediment filter.

What buyers wrote

These are verified purchases from our store, newest first. Nobody has left a review on the backwashing sediment tank yet, so there is nothing to show you there.

Frequently asked questions