Water Filtration Systems Reference
Why this matters
Customer water quality concerns drive upsell + recurring service revenue. Wrong filtration = inadequate solution OR damaged equipment. The plumber who diagnoses water issues + recommends proper system serves customer + secures long-term service relationship. This is the field card.
Common water quality issues
Hardness: calcium + magnesium; scale, soap scum, fixture buildup.
Iron: red/brown staining; metallic taste.
Sulfur (hydrogen sulfide): rotten egg smell.
Chlorine + chloramine: municipal disinfectant; taste + smell.
Lead: from old pipes / plumbing; health concern; EPA Lead + Copper Rule.
Nitrates: agricultural runoff; baby formula concern.
Bacteria (coliform, E. coli): well water testing required.
Sediment: visible particulate; well + city water.
TDS (Total Dissolved Solids): high TDS reduces taste + scale.
pH: too low (acidic) corrodes pipes; too high (basic) scaly.
VOCs (volatile organic compounds): chemicals; from industrial OR ag.
Filtration system types
Whole-house filter (point-of-entry, POE): filters all water entering home; sediment + carbon.
Point-of-use (POU): at single fixture; under-sink RO OR drinking water filter.
Water softener: ion-exchange; removes hardness.
Reverse osmosis (RO): removes 95 - 99% of dissolved solids; under-sink common.
UV light treatment: kills bacteria + viruses; for well water.
Iron filter (specialty): oxidation + filtration for iron-heavy water.
Acid neutralizer: raises pH on acidic water; calcite media.
Anti-scale device (electronic): alternative to softener; less proven effectiveness.
Whole-house sediment filter
Mesh screen (washable): removes large particulate.
Cartridge (5 - 30 micron): removes finer particulate.
Spin-down sediment filter: continuous-flush.
Replacement: 3 - 6 months typical.
Whole-house carbon filter
Granular activated carbon (GAC): removes chlorine, chloramine, taste + odor, some VOCs.
Carbon block: solid; removes more particulate.
Replacement: 6 - 12 months typical.
Water softener
Ion-exchange resin: replaces hardness ions with sodium.
Salt-based: most common; uses sodium chloride OR potassium chloride.
Salt-free (template-assisted crystallization): alters crystal form to prevent scale buildup; doesn't remove hardness.
Magnetic / electronic: limited effectiveness; some applications.
Sizing: grains per gallon × daily usage × regen frequency.
Typical residential: 32,000 - 60,000 grain capacity.
Resin replacement: 7 - 15 years lifespan.
Brine tank: stores salt for regeneration.
Regeneration: timer OR metered (preferred); flushes resin to discharge.
Reverse osmosis (RO) system
Multi-stage filtration: sediment → carbon → membrane → carbon → tank.
Stages:
- Sediment pre-filter (5 micron)
- Carbon pre-filter (chloramine removal)
- RO membrane (50 - 75 GPD typical residential)
- Storage tank (1 - 3 gal)
- Post-carbon filter
- Faucet dispenser
Removes: 95 - 99% TDS, lead, fluoride, arsenic, nitrate, chromium, sodium.
Doesn't remove: bacteria (need UV separately), some organics (carbon required separately).
Wastewater: 3:1 to 5:1 typical (3 - 5 gallons drain per gallon produced); newer systems 1:1.
Membrane replacement: 2 - 3 years.
Filter replacement: 6 - 12 months.
UV water treatment
UV-C light kills bacteria + virus: doesn't remove particulate OR chemicals.
Required for: untreated well water (per state code, typically).
Bulb replacement: annually.
Sleeve replacement: 5 - 10 years.
Water testing
Home test kit: pH, hardness, chlorine, basic parameters.
Laboratory test: comprehensive panel; bacteria, lead, nitrates, etc.
Required tests (for system specification):
- Hardness (grains per gallon)
- pH
- Iron, manganese
- TDS
- Specific contaminants of concern
Well water minimum: bacteria, nitrate (annually); coliform after any plumbing work.
System install considerations
Service interruption: water shut off during install.
Drain location: required for softener regen + RO waste.
Power: 120V outlet OR battery backup.
Salt loading: customer must add salt periodically.
Salt storage: bag storage area.
Bypass valve: maintains water flow during service.
Pre-filter sediment: protects equipment downstream.
Backflow prevention: code requirement at point of use.
Customer water concerns + recommendations
Hard water (white spots, soap scum): water softener.
Chlorine taste / smell: carbon filter (POU OR POE).
Iron stains: iron filter + softener OR RO.
Sulfur smell: aeration system OR oxidizing filter OR chlorination + filter.
Lead concern (old home): NSF-53 certified filter OR RO for drinking water.
Bacteria (well water): UV + filter.
Bottled water habit: RO under-sink saves money + plastic.
Whole-home protection: POE filter + softener + UV.
Common service tasks
Filter replacement: 6 - 12 months sediment + carbon; 2 - 3 years RO membrane.
Salt fill (customer): monthly typically.
Cleaning brine tank: 6 - 12 months.
Resin rebed (softener): 7 - 15 years.
UV bulb replacement: annually.
Water testing: annually for wells; periodically for city.
Common filtration mistakes
Skipping pre-filter (sediment damages downstream equipment). Wrong system for water concern (softener doesn't remove iron). Oversized softener (regenerates infrequently; bacteria growth in resin). Undersized (regenerates constantly; salt waste + early wear). Inadequate drain capacity for RO waste. Missing backflow preventer. Customer neglects salt refill.
Customer education
Salt level monitoring: customer must keep brine tank stocked.
Filter change schedule: built into service plan OR customer reminder.
Water test annually: especially well water.
Sediment in fixtures: replace pre-filter cartridge.
Smell return: replace carbon filter.
Decreased RO flow: replace pre-filters OR membrane.
Truck stock for filtration service
Sediment + carbon cartridges (multiple sizes), RO membranes (common sizes), RO pre/post filters, softener salt (40-lb bag), salt-tank cleaner, UV bulbs (common sizes), filter wrench, water test kit (basic field test).
Backflow prevention
Required for: irrigation, fire sprinkler, RO system (some jurisdictions), commercial.
Annual testing: certified tester for commercial.
Devices: RPZ (reduced pressure zone), DCV (double-check), AVB (atmospheric vacuum breaker).
When to recommend bottled / external service
Severe contamination: refer to remediation expert.
Heavy metals (uranium, arsenic, radioactive): specialized treatment.
Aging plumbing (lead service line): replacement priority.
References
- EPA Lead + Copper Rule
- NSF/ANSI Standards (42, 53, 58, 401, 372)
- Water Quality Association (WQA)
- Manufacturer technical data
- Manuall internal: Common Filter Types, Common Pipe Fittings