Choose a whole-house filter location by drawing the treatment boundary and checking the exact equipment’s service envelope. A universal 12–18-inch clearance or 10 PSI loss limit is not a placement specification. Different housings, tanks and controls need different space and operating conditions.
Draw the branches before choosing a wall
Mark the source, existing controls, water heater, indoor branches, outdoor taps and any current treatment. Identify which uses should receive the proposed treatment. A filter after a branch cannot treat that branch; a unit on the wrong line can consume capacity on water the owner never intended to treat.
Do not change well pressure-control arrangements from a generic diagram. The relationship between pump, pressure tank, switch and restrictions must remain appropriate to the well system. Have the installer confirm the chosen connection point and the treatment sequence.
Compare two candidate positions
| Constraint | Candidate A | Candidate B |
|---|---|---|
| Desired branches covered | Trace each branch | Trace each branch |
| Equipment and service envelope | Measure against manual | Measure against manual |
| Environmental limits | Check heat, freezing and exposure | Check heat, freezing and exposure |
| Drain or power where required | Confirm feasible route | Confirm feasible route |
| Isolation and access | Demonstrate reach and tool movement | Demonstrate reach and tool movement |
| Hydraulic effect | Assess added pipe/fitting and system losses | Assess added pipe/fitting and system losses |
Fill this in with measurements and installer findings, not a score. An essential requirement that fails cannot be outweighed by several conveniences.
Measure the removal path
The installed body dimensions are only the starting point. A sump may need to drop clear; a tank control or media change may require overhead access. Include support, valve travel, tubing bends, tools and a place for wet parts. Use a cardboard outline of the documented envelope if it helps check the space, but do not substitute it for the manufacturer’s clearance requirements.
A short pipe run may be attractive yet put the unit behind a fixed appliance. A slightly different route may improve service access but add hydraulic losses. Have both consequences evaluated before choosing.
Confirm the treatment order
Sediment, carbon, softening and disinfection have different purposes and feed requirements. Neither “carbon first” nor “softener first” applies to every analysis and product. Ask for a labeled treatment diagram showing why each stage sits where it does; our overview of how a whole-house filter works explains what each stage is for.
Pentair’s housing dimensions and limits illustrate the model-specific information to collect. Use the installation handover checklist to turn the selected position into an agreed job. This worksheet compares locations; it is not a plumbing design for every home.
Carry the selected location and branch map into the installation handover checklist .