RO Pre-Filter Housings in Stainless Steel
Stainless steel filter housings for the pre-filter stage in front of a reverse osmosis (RO) system. The pre-filter catches sand, rust and silt before they reach the membrane and the high-pressure pump. We sell the housing and the sediment cartridge; we do not sell RO membranes or carbon cartridges. For a sediment filter on a home's main supply, see whole house water filter housings.
Which housing for which RO system?
| RO system | Usual pre-filter | Our part |
|---|---|---|
| Small RO on one supply line | One 2.5 in x 10 or 20 in cartridge | 2.5 in housing with drain, 2.0 mm clamp housing or 1.5 mm clamp housing, 1/2 to 1 in NPT or BSP |
| Higher flow, whole-site RO feed | One 4.5 in jumbo cartridge, 10 to 30 in | 4.5 in jumbo housing, 1 to 2 in NPT or BSP, or tri-clamp ends |
| Commercial or industrial RO skid | Several 20 to 40 in cartridges in one vessel | Multi-cartridge housing, 3 to 7 cartridges, made to order |
Cartridges for the pre-filter
- PP melt-blown sediment cartridges, 1 or 5 micron, in 2.5 in and 4.5 in jumbo packs. These are thrown away when they block.
- Reusable stainless mesh cartridges (2.5 in and 4.5 in jumbo), 10 to 200 mesh or 1 to 50 µm. They can be rinsed and reused, and a coarse grade suits a first stage ahead of a finer PP cartridge.
Your membrane supplier sets the feed water limits for your system. Check their specification for the particle size and the chlorine limit before choosing the cartridge.
Points to check before you order
- Pressure. Put the pre-filter on the low-pressure side, before the high-pressure pump. Tell us your feed pressure and we will confirm the housing; we do not publish a pressure rating for the housings.
- Flow rate. Higher flow needs a larger cartridge or more cartridges. Send your RO feed flow and we will suggest a size.
- Chlorine. A sediment cartridge does not remove chlorine. Many RO membranes need a carbon stage as well; that is not part of our range.
- Salt or brackish water. Chlorides attack stainless steel. Choose SUS316 for these duties; see 304 vs 316 stainless steel.
- Connection. Order NPT or BSP to match your pipework, at the same price. See NPT vs BSP threads.
FAQ
Are your housings approved for drinking water?
No. Our housings do not carry NSF, WaterMark or other drinking-water approvals. Check your local rules before using them on a potable water supply.
Will a standard 10 in cartridge fit?
Our 2.5 in housings take cartridges about 60 mm in diameter. The 4.5 in jumbo housing takes cartridges about 102 mm in diameter. See the filter cartridge size guide to measure yours.
Can I put the housing after the high-pressure pump?
Send us the pressure at that point before you order. We confirm the housing for your conditions; we do not publish a pressure rating.
Do the housings come with cartridges?
Only if you choose a With PP Filter or With SS Filter option, offered on the 2.5 in and jumbo housings listed above. Housing Only and the multi-cartridge housings come without cartridges, so you can choose the cartridge your membrane needs.
How is shipping charged?
Standard housings and cartridges ship free to the UK, EU, Australia, New Zealand and the US. Multi-cartridge housings are quoted for shipping after the order. See the FAQ.
Need several housings for an RO project, or a size we do not list? Request a quote or see custom filter housings. Minimum order is one unit.