Uniformat D2020

Water heater, tankless gas

Also called on-demand water heater, instantaneous water heater, tankless

Confidence B
Version 0.3.0 (permanent link)
Reviewed 2026-10-22

This is version 0.3.0. The latest is 0.4.0.

Service life

20 yearsmedian of the stated lives · sources say 17–20 years

Years in service. The band runs from the shortest to the longest life the sources state, so it shows how much they disagree, not how long 80% of units last. The line is the median of the stated lives.

Basis

20 years · CNA e-Tool Estimated Useful Life Table, p10 · HUD CNA 3.4.1.2.4 “External tankless heater, gas or electric” — U.S. Department of Housing and Urban Development (planning life)
Same life for family and elderly properties. US multifamily housing. HUD's row covers gas and electric tankless heaters.
17 years · Energy Conservation Program: Energy Conservation Standards for Commercial Water Heating Equipment (final rule), 88 FR 69686, October 6, 2023, p70 · IV.F.6 “Table IV.21: "Gas-fired instantaneous water heaters and hot water supply boilers: Tankless water heaters ... 17" years” — U.S. Department of Energy (planning life)
Printed page 69755. class: commercial gas-fired tankless (instantaneous) water heaters.
20 years · Energy Conservation Program: Energy Conservation Standards for Consumer Gas-fired Instantaneous Water Heaters (final rule), 89 FR 105188, December 26, 2024, p43 · IV.F.6 “"DOE estimates the average product lifetime to be around 20 years for instantaneous water heaters"” — U.S. Department of Energy (planning life)
Printed page 105230. residential: consumer gas-fired instantaneous water heaters (<2 gal, >50,000 Btu/h). Table V.2 (p.75, printed 105262) shows 20.0 years average lifetime at every efficiency level.

How sources are chosen and recorded: sourcing policy.

Municipal lives for plumbing (D20)

26 municipalities in Ontario and British Columbia state a life for plumbing as a whole, in 18 distinct tables: 15–50 years, median 25. 34 rows come from capital asset policies (accounting lives, used for amortization) and 1 from asset management plans (planning lives, used to forecast replacement). They describe the system rather than this component, and none is a measured life.

Years. Each dot is one stated life and each bar a stated range; equal values stack. Hollow marks are planning lives from asset management plans; filled marks are accounting lives from policies. The dashed line is the median. Policies that copy the same table count once.

All 27 stated lives

Municipality	As written	Years	Kind	Source
Kingston	Building Fixtures	15	accounting	p15 · 2016
Meaford	Plumbing - Water Treatment System	15	accounting	p17 · 2020
Trent Lakes	Mechanical Systems - Fixtures	15	accounting	p10 · 2009
Fort St. James, Revelstoke, Rossland, Sicamous, Tumbler Ridge · same table	Electrical/Plumbing/Fire	15–20	accounting	p5, p9, p7, p9, p5 · 2010
Okanagan-Similkameen	Electrical/Plumbing/Fire	15–20	accounting	p11 · 2023
Salmo	Electrical/Plumbing/Fire	15–20	accounting	p6 · 2016
Comox Valley	HVAC systems, mechanical, plumbing, wiring, etc.	20	accounting	p6 · 2010
Cranbrook	HVAC, plumbing, lighting, etc	20	accounting	p9 · 2010
Telkwa	Electrical/Plumbing/Fire	20	accounting	p8
London	Building Components - Services (HVAC, lighting, communication, plumbing etc.)	20	accounting	p2 · 2023
Meaford	Plumbing - Fixtures	20	accounting	p16 · 2020
Meaford	Plumbing - Boiler	20	accounting	p17 · 2020
Lantzville	Electrical, Mechanical, Plumbing	25	accounting	p11 · 2019
Meaford	Plumbing - Septic System	25	accounting	p17 · 2020
Rainy River	Building Improvements - Electrical/Plumbing	25	accounting	p11 · 2010
Rainy River	Building Improvements - Electrical/Plumbing	25	planning	p17 · 2026
The Blue Mountains	Septic System	25	accounting	p11 · 2019
Bancroft, Centre Hastings, Hastings Highlands, Wollaston · same table	Electrical/Plumbing	25–30	accounting	p5, p4, p6, p5
Greater Napanee	E30 Chillers, Rink Piping, Fuel Storage Tanks	30	accounting	p16 · 2012
Grey Highlands	Septic System	30	accounting	p11 · 2026
The Blue Mountains	Plumbing System	30	accounting	p11 · 2019
Trent Lakes	Mechanical Systems - Piping	30	accounting	p10 · 2009
Parksville	Plumbing Infrastructure	50	accounting	p9 · 2023
Greater Madawaska, Quinte West · same table	Piping	50	accounting	p17, p38 · 2025
Meaford	Plumbing - System	50	accounting	p16 · 2020
Meaford	Plumbing - Cistern	50	accounting	p16 · 2020
The Blue Mountains	Cistern	50	accounting	p11 · 2019

Of 35 rows, 2 were compared with an image of their page; 33 were matched to their page automatically (the label and number appear in the page text). Follow the page link before relying on an automatically matched row. About the policies · All approved rows as JSON

Preventive maintenance

1 tasks in 1 work order.

1
2
3
4
5
6
7
8
9
10
11
12Annual

Months from the schedule start. Download the tasks as CSV for a CMMS, or ask the MCP tool get_pm_schedule for dated visits.

Annual · 1 task

Source: Good estate management for schools: Compliance tracker, Compliance tracker, sheet "Tracker", ref 20

Task	Page
Gas safety inspection and servicing of gas appliances	pundefined

Frequencies are ISO 8601 durations in the data (P3M = every 3 months).

Open questions

Every source here is a published planning, design or accounting life. None is observed replacement data.
Written for schools in England; several rows are statutory safety checks under UK law rather than equipment maintenance.

Know the answer? Send it with a source to [email protected].

Cite this

Citation

unfinished.one (2026). Water heater, tankless gas, v0.3.0. https://unfinished.one/c/water-heater-tankless/v/0.3.0

BibTeX

@misc{unfinished_water_heater_tankless_0_3_0,
  title = {Water heater, tankless gas},
  author = {{unfinished.one}},
  year = {2026},
  version = {0.3.0},
  url = {https://unfinished.one/c/water-heater-tankless/v/0.3.0},
  note = {CC BY 4.0}
}

Licence CC BY 4.0 · How to cite · JSON · Versions: 0.4.0, 0.3.0, 0.2.0, 0.1.0