1) Layout: mark fixture locations on plates/floor per plan. Verify clearances. 2) DWV (drain-waste-vent): Start from building drain/sewer connection, work UP. Minimum slopes: 1/4 in/ft for 3 in and smaller, 1/8 in/ft for 4 in and larger. Install main stack (3-4 in), branch drains (1.5-2 in), vent risers (1.5-2 in). Cleanouts at base of stacks, every 100 ft horizontal. 3) Test DWV: air test (5 psi, 15 min) or water test (10 ft head, 15 min). Fix all leaks. 4) Supply: install main water line (3/4-1 in), branch to fixtures. PEX: home-run (manifold) or trunk-and-branch. Copper: solder/ProPress. Hot water line: insulate in unconditioned spaces. PRV (pressure reducing valve) if street pressure >80 psi. 5) Gas: black iron or CSST from meter to appliances. Test: 3 psi for 10 min, soap test all connections. 6) Fixtures rough dimensions: toilet rough 12 in from finished wall, lavatory drain 17-19 in height, shower drain centered. Call for rough inspection before closing walls. CSI 22 10 00.