Sediment filters are the cheapest, most overlooked piece of equipment on a well system, and they’re also the first component field diagnostics point to when troubleshooting low pressure. A clogged or wrong-sized sediment filter causes more mystery low-pressure complaints than any other single component. It’s also the first stage in almost every whole house well water filtration system, so getting it right protects everything installed after it.
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Micron Rating: The Number That Actually Matters
Micron rating tells you the smallest particle size a filter catches. A 5-micron filter catches finer sediment than a 50-micron filter. Lower numbers mean finer filtration, but also faster clogging and more pressure drop. Most wells do best with a two-stage setup: a coarser 20 to 50 micron filter to catch the bulk of the sand and grit, followed by a finer 5 to 10 micron filter to polish what’s left.
Spin-Down vs. Cartridge Filters
Spin-Down Sediment Filters
A spin-down filter uses a reusable mesh screen you flush manually by turning a valve, sending trapped sediment out a small drain port. No replacement cartridges needed, which makes it the top recommendation for wells with heavy sand or grit, since it avoids burning through cartridges weekly. Installed cost runs $150 to $350.
Cartridge Filters
A standard cartridge housing takes a replaceable filter element, usually string-wound or pleated. Cheaper per unit upfront, but you’re buying replacement cartridges every 3 to 6 months. Good option for moderate sediment loads where a spin-down’s coarser filtration isn’t quite fine enough. Installed cost runs $80 to $250 for the housing, plus $10 to $25 per cartridge.
Sizing for Flow Rate, Not Just Pipe Size
A sediment filter has to be rated for your home’s actual peak flow rate. A standard 10-inch cartridge housing handles roughly 8 to 10 GPM before pressure drop becomes noticeable. Bigger households running multiple fixtures at once, or homes with higher-flow fixtures, often need a 20-inch housing or a larger big-blue style unit rated for 15 to 20 GPM instead.
| Household Flow Need | Recommended Housing | Installed Cost |
|---|---|---|
| Under 8 GPM (1 to 3 people) | Standard 10-inch cartridge housing | $150 to $300 |
| 8 to 12 GPM (typical family home) | 20-inch cartridge housing or spin-down | $250 to $450 |
| 12+ GPM (larger household, high fixture count) | Big-blue dual housing or spin-down plus cartridge combo | $400 to $700 |
Signs Your Current Filter Is Undersized or Clogged
- Water pressure that drops noticeably a few days after a fresh cartridge change
- Visible grit settling in toilet tanks or water heater sediment buildup, despite having a filter installed
- A pressure gauge before and after the filter housing showing more than a 10 PSI difference
- Downstream equipment (softener, iron filter) needing service more often than expected
What Housing Material Actually Matters
Clear housings let you see cartridge condition at a glance, which is useful for quick visual checks, but they can degrade faster in direct sunlight or high-iron water that stains the plastic. Opaque housings hold up better long-term in most basement or utility room installs. Either works fine; pick based on whether visual inspection without removing the cartridge matters.
When to Call a Pro vs. DIY
Installing a sediment filter housing on an accessible section of pipe, and swapping cartridges going forward, is one of the most beginner-friendly DIY jobs on a well system. A housing wrench and a spare cartridge on hand are usually all that’s needed to handle this without professional help. It’s one of the easiest items to fold into a monthly maintenance routine. Professional installation is generally worth it only when the main line sits in a tight or hard-to-access spot, or when adding a spin-down unit that needs a new drain line run.
Check your current filter this weekend. If you can’t remember the last time you changed it, that’s probably your answer for why pressure feels a little low.