Whole-House Water Filtration Systems
Why this matters
Whole-house water filtration is one of the highest-ticket plumbing add-ons: a large install ticket plus recurring media and cartridge service every year after. The customer concern: city water has chlorine + chloramine + sediment + occasional trace contaminants; well water has iron, manganese, hardness, sulfur, sometimes coliform. Bottled water doesn't solve shower + laundry + cooking exposure. The whole-house solution does - IF designed for the customer's water source + contaminant profile. Generic "one-size" systems disappoint; properly-sized + sequenced systems deliver durable customer satisfaction + recurring filter revenue.
Water testing - the design step
Before quoting any filtration:
City water: free Consumer Confidence Report from the utility lists treated contaminants. Common concerns: chlorine, chloramine, trihalomethanes, sometimes lead from premises plumbing.
Well water: customer-paid test at state lab OR certified water lab:
- Basic: pH, hardness, iron, manganese, TDS, sulfate
- Bacterial: coliform, e. coli
- Advanced: arsenic, radium, nitrate, lead, pesticides
- Test annually for well; every 5 yr for city
Visual + customer report:
- Sediment in faucet aerator → install sediment filter
- Hard water (white scale on faucets, soap won't lather) → softener or TAC
- Reddish stains on fixtures → iron + manganese (water treatment)
- Sulfur smell → H2S
- Chlorine smell → activated carbon
- Cloudy water → sediment, turbidity, OR air
Quote = filtration matched to test results, not a generic package.
System architecture
A sequence of stages targets specific contaminants:
- Sediment (5 - 50 micron pleated/string-wound): catches sand/silt/rust. Replace 3 - 12 months.
- Activated carbon (GAC cartridge or backwash tank): removes chlorine, chloramine (catalytic), VOCs, taste/odor. Replace 6 - 18 mo or backwash quarterly.
- Iron/manganese/H2S (well only): iron filter (greensand, Birm, AIO) + oxidation pre-stage. Solves orange staining + sulfur smell.
- Softener (hard water): ion exchange; salt-regenerated every 7 - 14 days. See Salt-Free Alternatives for TAC option.
- UV sterilization (well water, optional): specify NSF/ANSI 55 Class A (40 mJ/cm²) on any supply that has to be made potable. Class B units (16 mJ/cm²) are supplemental polish on water already known to be safe, not an answer to a coliform-positive well. Annual lamp, and clean the quartz sleeve on the same visit.
- RO (point-of-use at drinking tap typically): removes 95 - 99% TDS.
Typical configurations
City water light: sediment cartridge + activated carbon cartridge; cartridges 2 - 4x/year.
City water mid-range: sediment + backwashing carbon tank (1.0 - 2.0 cu ft media); annual change; 99%+ chlorine/chloramine removal.
City water premium: sediment + catalytic carbon tank + salt softener (if >7 grains hardness) + optional UV; 10-yr tank media life.
Well water basic: sediment + iron filter (if >0.3 mg/L) + softener (if >5 grains) + UV.
Well water complex: aeration oxidation + sediment + backwash iron/Mn + carbon + softener + UV + kitchen RO.
Specific contaminants: arsenic (ion exchange or Bayoxide E33/GFH), nitrate (ion exchange or POU RO), bacteria (chlorination + retention + carbon + UV), radon (aeration tank with vent).
Tank vs cartridge
Cartridge filters
- Lower upfront
- 1 - 10 GPM flow per stage
- Replace cartridges 2 - 4x/year
- Customer-DIY replacement
- Best for low-flow + light contamination
Backwashing tank
- Higher upfront
- 10 - 25 GPM flow capacity
- Backwash flushes media weekly OR per schedule
- Service annually
- Best for high flow OR heavy contamination
Most whole-house systems mix: sediment cartridge + activated carbon backwashing tank + softener tank, for example.
Sizing for flow
The system must handle peak simultaneous demand without pressure drop:
- 1-bathroom home: 8 - 10 GPM
- 2 - 3 bathroom home: 12 - 15 GPM
- 4+ bathroom home: 15 - 25 GPM
- Commercial: per fixture count
Each cartridge / tank rated for max flow without exceeding pressure drop spec. Undersized = low water pressure when multiple fixtures run.
Installation considerations
Location: cold-water inlet to house, after pressure regulator, before water heater + softener. Each tank/cartridge needs bypass valves (3-valve combo common). Backwash tanks need drain (1.5 - 4 GPM): floor drain, sump pump, or outdoors (varies by jurisdiction). Backwash controllers + UV need 120V GFCI. Include test ports pre + post each stage. Sediment-stripper valve before whole system for post-install flush.
Service schedule
Cartridge change 3 - 12 months per stage (customer-DIY or plumber). Salt refill 3 - 8 weeks. UV bulb + sleeve cleaning annual. Annual whole-system service: water test at multiple points, cartridges, backwash controller verification, salt check, UV assessment.
Customer education
The "why" conversation:
- "Chlorine in your shower water vaporizes - you're inhaling it"
- "Hard water won't make you sick, but scale is what costs you the water heater." Independent testing done for the Water Quality Association found storage water heaters run on hard water lose a meaningful share of their rated efficiency as scale builds, while units on softened water held close to rated. Keep the claim inside what the testing covered - heater efficiency and scale-driven wear on fixtures - and do not stretch it into a blanket lifespan percentage for every appliance in the house
- "The water from your kitchen tap travels through 30 ft of plumbing in your house - that's where most lead exposure happens, not at the utility"
Personalize to the customer's specific concerns + test results. Customers with general "I want clean water" get a generic system; customers with named concerns get a fitted system + buy it.
Common mistakes
Generic system without testing: customer ends up with iron filter on water that doesn't have iron, OR no softener on hard water. Wasted equipment.
Undersized flow: 8 GPM system on 4-bathroom home; pressure drops with multiple fixtures.
No bypass valves: service requires shutting whole house off.
Skipping pre-sediment filter: media in downstream tanks clogs fast without sediment removal upstream.
Forgetting backwash drain: tank installed but no drain path → water damage.
Wrong tank-mount for water hammer: rigid mounting transmits shock to plumbing.
NEVER size whole-house filtration without a verified WATER TEST + a PEAK FLOW CALCULATION. The customer wants a "good filter system" + has the budget; the plumber who installs based on "what they sold us last week at supply" delivers either an oversized + undersold system OR an undersized system that disappoints. The 30-minute water test + 15-minute fixture count = the right design. Without that data, you're guessing - + the warranty claims that result will erase the margin from 10 jobs.
References
- NSF / ANSI 42 (Aesthetic Effects - Chlorine, Taste)
- NSF / ANSI 53 (Health Effects - Lead, VOCs, Cyst Reduction)
- NSF / ANSI 44 (Cation Exchange Water Softeners)
- NSF / ANSI 55 (Ultraviolet Microbiological)
- EPA Drinking Water Standards
- Manuall internal: Water Quality Treatment, Salt-Free Water Treatment Alternatives, Well Water Systems