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Water System Builder

By the Home Water HQ research desk · Updated November 2026 · Prices verified 2026-11-03 · Certification data verified 2026-11-05

Build it here, buy it on Amazon. Tick what your water test flags and the builder assembles a stage-by-stage system from our 39-product verified dataset — checking flow rates, connection sizes, stage order, and manufacturer limits as it goes. Anything it can't check is labeled uncheckable, never passed silently. Shopping one filter instead? Try the contaminant finder.

Design your system

Step 1 — Your water source
Step 2 — What's in your water (tick all your test flags)
Step 3 — Hardness
Step 4 — Bathrooms (sets your peak flow estimate)
Step 5 — Drinking water

Your build appears here — stage by stage, with the compatibility check printed underneath.

How the checks work. Flow: your bathroom count sets a peak-flow planning estimate; every point-of-entry stage's manufacturer-published service flow must clear it, and the build's real flow is its slowest stage. Figures a maker publishes only as a maximum are labeled as such. Connections: mixed 1-inch and 3/4-inch stages are flagged for reducer fittings — a note, not a failure. Order follows standard practice: sediment protects everything, iron comes out before a softener (it fouls resin), UV goes last and only behind sediment control. Coverage keeps the dataset's certified-vs-manufacturer-claimed labels per contaminant, and a contaminant no stage treats prints as a gap. Full method: How we compare.