When your water filter housing cracks, leaks, or the threads strip, you don't need to replace the entire filtration system. The Flow-Pur FH4200WW12 is a universal replacement housing that fits most standard 10" water filter installations. Whether it's an RV fresh water system, under-counter filter, or whole-house point-of-entry system, this housing provides a cost-effective replacement solution.
Built by Watts Water Technologies (formerly Flow-Pur), this housing meets the same industrial standards as OEM installations. The heavy-duty construction and quality materials ensure years of reliable service, while the universal design means it's likely to fit your existing mounting bracket and plumbing connections.NSF GradeFDA Approved125 PSI
Replaces most 10" filter housings
Reinforced ribs, thick walls
100% polypropylene construction
Buttress threads with EPDM O-rings
The FH4200WW12 is manufactured from 100% polypropylene that meets NSF (National Sanitation Foundation) and FDA (Food and Drug Administration) standards for potable water contact. This ensures the housing material won't leach chemicals into your drinking water or affect taste and odor.
Benefits of Polypropylene Construction:
Unlike standard threaded housings, the FH4200WW12 features buttress threads that provide superior sealing and security. The buttress design distributes stress more evenly across the threads, preventing cracking under pressure. Combined with compressible EPDM O-rings in the cap, sump, and top seat, this creates multiple layers of leak protection that stay sealed even with thermal expansion and pressure cycling.
The housing features thick sidewalls with heavy-duty reinforcing ribs for greater strength and durability. This reinforced design prevents cracking under pressure and provides long-term reliability even in demanding applications like RV systems that experience constant vibration and movement.
Pressure & Temperature Ratings:
The FH4200WW12 accepts standard 9-3/4" long x 2-1/2" diameter filter cartridges from Flow-Pur and most other manufacturers. This includes sediment filters, carbon block filters, pleated filters, and specialty cartridges for specific water treatment needs. The standard sizing ensures you'll have plenty of filter options for different water quality issues.
Inlet/Outlet Connections: 1/2" NPT (National Pipe Thread) female connections on both inlet and outlet. This is the most common size for residential and RV water filtration systems.
Mounting: The housing is designed to work with most standard filter housing mounting brackets. If your existing bracket is damaged, replacement brackets are available separately.
Installation Notes: When replacing an existing housing, it's important to replace the O-rings even if they appear to be in good condition. Old O-rings may not seal properly against the new housing surface.
Filter Wrench (SKU 88-2113): Essential tool for removing and installing filter housings. The plastic wrench fits the housing perfectly and prevents damage to the threads. Replacement O-Ring Set (SKU 88-2116): Replace O-rings during housing replacement or every few cartridge changes to maintain proper sealing. Winterizing Bypass Plate (SKU 88-2435): For RV applications, allows bypassing the filter during winterization to prevent filling the housing with antifreeze. #8 Filter Cartridge (SKU 88-2108): Popular general-purpose filter cartridge for the housing.
RV Fresh Water Systems: Replace cracked or damaged housings in RV water filtration systems. The vibration-resistant construction makes it ideal for mobile applications.
Under-Counter Filtration: Kitchen or bathroom sink filtration systems where the housing is mounted underneath the counter.
Point-of-Entry (POE): Whole house filtration systems where water is filtered as it enters the home or RV.
Well Water Systems: Pre-filtration in well water systems to remove sediment before it reaches other equipment.
Marine Applications: Boat and yacht fresh water systems where corrosion resistance is important.
The FH4200WW12 is the housing only. Filter cartridge is sold separately. Make sure to order the appropriate filter cartridge for your water treatment needs. Common options include sediment filters, carbon block filters, and combination filters that address multiple water quality issues.
Before Installation: Shut off water supply and relieve pressure in the lines. Have a bucket ready to catch any remaining water in the old housing.
O-Ring Maintenance: Lightly lubricate O-rings with food-grade silicone lubricant or petroleum jelly before installation. This helps prevent pinching and ensures proper sealing.
Tightening: Hand-tighten the housing until the O-ring contacts the sump, then tighten an additional 3/4 turn with the filter wrench. Over-tightening can damage the threads or O-rings.
Testing: After installation, slowly turn on water supply and check for leaks. If leaking occurs, turn off water and check O-ring positioning.
Regular O-Ring Replacement: Replace O-rings every 12-18 months or whenever you notice any signs of wear, cracking, or hardening. Clean Housing Interior: When changing filters, clean the inside of the housing with a mild bleach solution (1 tsp per quart of water) to prevent bacteria buildup. Monitor for Cracks: Inspect the housing regularly for stress cracks, especially around the threaded areas. Replace immediately if cracks are found. Proper Storage: If removing the housing for extended periods, store it in a dry location away from direct sunlight to preserve the polypropylene material.
• Cracked or damaged filter housings • Housings with stripped or worn threads • Old housings that no longer seal properly • OEM housings installed by RV manufacturers • Under-counter filter system upgrades • Any 10" standard filter housing installation
Essential: • Filter wrench for installation/removal • Appropriate filter cartridge for your water Recommended: • Extra O-ring set for future maintenance • Food-grade silicone lubricant for O-rings • Mounting bracket (if replacing damaged bracket) For RV Use: • Winterizing bypass plate for seasonal storage
SKU 88-2113: Flow-Pur Exterior Canister Water Filter Wrench SKU 88-2116: Flow-Pur Replacement O-Ring for Microbiological Filter SKU 88-2108: Flow-Pur Ext Canister Single #8 Replacement Filter SKU 88-2435: Flow-Pur Winterizing Bypass Plate Order these accessories with your housing for complete installation readiness.
• Always shut off water supply before installation • Relieve pressure in water lines before removing old housing • Use proper thread sealant on NPT connections • Do not over-tighten – this can damage threads or O-rings • Test system thoroughly for leaks before putting into service • If unsure about installation, consult a qualified plumber
• Housing only – Filter cartridge sold separately • Fresh water use only – Not for hot water applications • Maximum 125 PSI / 125°F – Do not exceed rated pressure or temperature • Replace O-rings – Always use new O-rings when installing • Proper torque – Hand-tighten plus 3/4 turn with wrench • Regular inspection – Check for cracks or wear during filter changes • Professional installation recommended – If unsure about plumbing connections