{"id":"water-heater-gas-tank","version":"0.1.0","classification":{"uniformat":"D2020"},"names":["Water heater, gas, storage tank"],"aliases":["DHW tank","HWT","hot water tank","domestic hot water heater","gas water heater"],"service_life":{"median_years":13.5,"range_years":[12,15],"range_basis":"source_spread"},"pm_tasks":[],"basis":[{"type":"public_document","life_type":"planning","title":"CNA e-Tool Estimated Useful Life Table","by":"U.S. Department of Housing and Urban Development","url":"https://www.hud.gov/sites/documents/eul_for_cna_e_tool.pdf","page":10,"code":"HUD CNA 3.4.1.2.6","label":"Residential hot water heater, gas or electric","years":[12,15],"note":"Family properties 12 years, elderly 15. US multifamily housing."}],"confidence":{"grade":"C","sample_size":null},"open_questions":["HUD's row is for residential water heaters; commercial storage heaters may differ.","Only one source so far: HUD planning lives for US multifamily housing. Canadian and observed sources are needed.","No preventive maintenance tasks are sourced yet."],"contributors":["unfinished.one editors"],"last_reviewed":"2026-10-21","canonical_url":"https://unfinished.one/c/water-heater-gas-tank","versioned_url":"https://unfinished.one/c/water-heater-gas-tank/v/0.1.0","licence":"CC-BY-4.0","citation":"unfinished.one (2026). Water heater, gas, storage tank, v0.1.0. https://unfinished.one/c/water-heater-gas-tank/v/0.1.0"}