Water Filtration System Inspection

Per EPA and NSF guidelines, a comprehensive water test must be performed before selecting a filtration system. Testing should include: pH, hardness, TDS, chlorine/chloramine, iron, manganese, lead, bacteria (coliform), nitrates, and any local contaminants of concern. The filtration system must be selected to address specific contaminants found.

1. Verify a laboratory water test was performed (not just test strip)

2. Review results for key contaminants: lead, bacteria, nitrates, VOCs, PFAS

3. Confirm selected filter system is NSF-certified to remove identified contaminants

4. Check that treatment matches water source (municipal vs. well have different needs)

5. Verify filter capacity matches household daily water usage

- No water test performed — wrong filter type selected

- Filter not certified for the contaminants present (marketing claims vs. NSF certification)

- Well water with bacteria — requires UV or chlorination, not just carbon filter

Per NSF standards, filter type must match contaminants: sediment filter (particles >5μm), carbon block (chlorine, VOCs — NSF 42), catalytic carbon (chloramine), reverse osmosis (lead, TDS, PFAS — NSF 58), UV (bacteria, viruses). Whole-house systems treat all water; point-of-use (POU) systems treat drinking water only. Flow rate must match household demand.

1. Verify system type matches water test results (sediment, carbon, RO, UV, or combination)

2. Check NSF certification number on the specific model for specific contaminants

3. Confirm flow rate: whole-house systems need 10–15 GPM for typical homes

4. For RO systems: check waste water ratio (3:1 or better is efficient)

5. Verify filter replacement schedule and availability of replacement cartridges

6. Check system includes pressure gauge for monitoring filter condition

- Carbon filter used for bacteria — ineffective, need UV or chlorination

- Whole-house RO (unnecessary and expensive) — RO typically only needed at drinking point

- System flow rate too low — water pressure drops when multiple fixtures run

Per DTU 60.11 & NF EN 12056, whole-house filters install after main shutoff and pressure regulator, before water heater and distribution. Point-of-use systems install at the specific fixture (under sink is most common). All systems need accessible location for filter changes. RO systems require drain connection and adequate space for tank.

1. Whole-house: verify installation after main shutoff, before water heater

2. Point-of-use: verify installation at intended fixture with proper clearance

3. Check adequate space for filter housing removal and cartridge changes

4. For RO systems: confirm space for storage tank (typically 12"×12"×18")

5. Verify drain connection available for RO waste water and backwash systems

6. Check electrical outlet available for UV systems (must be RCD-protected)

- Filter housing in tight space — cartridge changes impossible without removing the system

- RO tank too far from faucet — slow flow at tap

- UV system without RCD outlet — shock hazard in wet environment

Per DTU 60.11 & NF EN 12056, all connections must use approved materials and fittings. Bypass valve required for whole-house systems to allow water service during filter changes. Connections must handle full system pressure. Push-fit fittings must be on supported rigid pipe. All joints must be leak-tested.

1. Verify inlet/outlet orientation matches filter flow direction (arrow on housing)

2. Check bypass valve installed and functional (whole-house systems)

3. Test all connections for leaks under full pressure

4. Verify shutoff valves on inlet and outlet

5. For RO: check feed water connection, tank connection, and drain saddle valve (or drill connection)

6. Confirm faucet installation is secure and leak-free (POU dedicated faucet)

- Filter installed backwards (against flow arrow) — reduced filtration, high pressure drop

- No bypass valve — no water during filter changes

- Saddle valve for RO drain (prone to clogging) — direct drain connection preferred

Per manufacturer specifications, filter cartridges must be properly seated with O-rings lubricated and intact. Multi-stage systems must have cartridges in correct order (sediment → carbon → specialty → RO membrane). UV lamps must be installed per manufacturer orientation. All systems must be flushed per manufacturer instructions before first use.

1. Verify cartridge order in multi-stage systems (sediment first, finest filtration last)

2. Check O-rings are properly seated, lubricated, and not pinched or cracked

3. Confirm housing is hand-tightened (not over-torqued — cracks housing)

4. For RO: verify membrane orientation (flow direction per manufacturer)

5. For UV: confirm lamp is seated, sleeve is clean, and ballast indicator is green

6. Verify system was flushed for recommended time before use (typically 5–10 minutes)

7. Record installation date for replacement scheduling

- O-ring pinched during assembly — causes bypass leak, unfiltered water passes through

- Cartridges in wrong order — premature clogging of expensive specialty filters

- System not flushed — carbon fines in first water use

Per NSF guidelines and manufacturer specifications, filtered water must be tested to verify contaminant removal meets stated performance. Pressure drop across the system should be less than 5 PSI for whole-house (clean filter). RO systems should produce water with TDS reduction of 90%+ from feed water. Flow rate must meet household needs.

1. Test filtered water: chlorine removed, TDS reduced (RO), taste/odor improved

2. Measure pressure before and after filter — drop should be <5 PSI (clean cartridge)

3. For RO: measure TDS of feed water and product water (expect 90%+ reduction)

4. Check flow rate at filtered faucet — adequate for intended use

5. Verify no leaks at any connection point under sustained pressure

6. Test UV system: verify flow sensor operates, lamp indicator shows operational

7. Run water for 10+ minutes and recheck — some issues only appear under sustained flow

- TDS not reduced sufficiently (RO) — membrane installed incorrectly or defective

- Excessive pressure drop — pre-filter clogged or undersized system

- Slow RO flow — tank not pre-charged to proper air pressure (7–8 PSI empty)