Methodology
Last updated November 9, 2026
Every number on this site is either sourced or labelled as an estimate. This page explains the difference, and how a claim gets from a source document to a published page.
1. Primary sources first
For a tub we work from the manufacturer's spec sheet and installation manual: exterior and interior dimensions, seat height, step-in threshold, water capacity, door-seal design and the electrical requirement. For accessibility dimensions we use ICC/ANSI A117.1 and published ADA guidance. For labour and permit questions we use the state licensing board and the local permit office named on the city page.
2. Cost models show their inputs
Installed cost is modelled from visible inputs: the material or equipment price, the labour and access scope (excavation, drain, electrical, permit), consumables, and a reserve for service or repair. We do not present a single "average cost" as if it were a quote; the range and what it includes are stated on the page.
3. How options are compared
We compare step-in height, seat and transfer options, door-seal design and serviceability, water capacity against the household's hot-water supply, and the warranty's exclusions. A product earns a recommendation when it meets the stated criteria for a stated need; it cannot buy a place in a ranking.
4. What we have not tested
We do not run a laboratory or a crew, and we do not carry out every job we write about. When a claim comes from a manufacturer document, an adopted code, a certification listing or a contractor report, we say which. We do not imply first-hand testing we did not perform.
5. Sources we work from
| Source type | What it decides | How it is cited |
|---|---|---|
| Manufacturer spec sheets and installation manuals | Dimensions, seat height, water capacity, door-seal design | Spec reproduced with the model named |
| ICC/ANSI A117.1 and published ADA guidance | Accessible-bath dimensions and clearances | Standard or guidance named |
| State licensing boards | Which trade may do the plumbing and electrical work | Board named, with its lookup link |
| Local permit offices | Whether a tub replacement needs a permit and inspection | Office named, with its link |
| Published US price guides | Installed cost bands | Band with the month it was checked |
When two sources disagree, the page says which one it followed and why. A figure that cannot be traced to a document is labelled an estimate, and an estimate is never presented as the price of a specific job.
6. Listings and directory data
The service-area directory is compiled from public business records: the firm's own website, its published address and phone number, and the state or city licence register named on the city page. A record is marked verified only when the name, address, phone and licence have been checked against those sources and the date of the check recorded; everything else is labelled. Where a source does not publish a ZIP code or a website, the field is left blank rather than guessed, and the page says "not published".
7. Corrections
If a code, a specification or a listing changes, we update the article and its "last updated" date. Emailcontact@walkintublab.com with the page and the correction.