Cost research is only as good as its inputs. This page lists what goes into our figures and, just as importantly, what we refuse to use.
Source categories and their weight
| Source | What it gives us | Weight | Known bias |
|---|---|---|---|
| Reader-submitted quotes and paid invoices | Real prices, real cities, with length and depth | Highest | Skews toward larger, memorable jobs; small repairs are under-reported |
| Published contractor pricing (regional plumbing companies) | Per-foot rates and worked examples for a named market | High | Marketing material — headline rates are optimistic and often exclude restoration |
| Municipal permit fee schedules and cost-share programmes | Exact administrative costs, right-of-way rules, subsidy ceilings | High for what it covers | Only covers the paperwork portion, never the labour |
| Materials and equipment pricing | A floor: nothing legitimate can cost less than materials plus a plausible labour day | Moderate — used as a sanity check | Ignores overhead, mobilisation and warranty |
| Search demand and query data | Which questions homeowners actually ask, and which are rising | Editorial planning only | Never used to set a price |
Standards and regulatory references
Where we describe how work is done or what is required, we work from the documents that actually govern it rather than from other websites:
- Model plumbing codes — the Uniform Plumbing Code (IAPMO) and the International Plumbing Code (ICC), as adopted and amended state by state. Adoption is never uniform, which is why we always tell you to check locally.
- ASTM F1216 and related standards — the reference for cured-in-place pipe (CIPP) rehabilitation, which is what makes a lining warranty meaningful or meaningless.
- NASSCO PACP — the Pipeline Assessment Certification Program, the grading vocabulary a competent inspection report should use. When we explain how to read a scope report, this is the scale we are teaching.
- Municipal ordinances — for point-of-sale lateral inspection requirements, backflow prevention mandates and responsibility boundaries. Cited by city, because they differ by city.
- State licensing boards — for who is legally permitted to perform and certify the work.
What we deliberately do not use
- Other cost-aggregator websites. Copying a range from a site that copied it from a third produces a number with no traceable origin. It is also how a single early error propagates across an entire industry.
- Contractor-supplied “average cost” press releases. Written to justify a price, not to describe a market.
- Lead-generation network data. Structurally biased toward the jobs that generate commissions.
- Anonymous forum figures without a city and a date. A price without a place and a time is not data.
Freshness and versioning
Every figure carries a survey date. Cost ranges are re-pulled quarterly; the current baseline is August 2026. Regulatory content is reviewed at least annually and immediately whenever a reader reports a change. Pages show their most recent review date, not merely their publication date.
When a re-pull moves a band materially, we update the figure and note the change on the page rather than quietly overwriting it. A reader who quoted our number to a contractor last quarter deserves to know it moved.
Contribute data
The reader-submitted category is the one that improves fastest, and it is the one that makes our state pages worth more than a national average. If you have a quote or a paid invoice, send it to 
with:
- the city and state;
- the run length in feet, and the depth if you know it;
- the method quoted — open trench, lining, bursting, spot repair, cleaning;
- the total, and whether permits and restoration were included;
- the date of the quote.
Strip your name and address first: we only need the numbers. Contributors are credited here on request, and never identified without explicit permission.
Requests from researchers
Journalists, academics and municipal staff can request the underlying ranges for a specific cohort. Write to us with what you need and your deadline. We do not release reader-submitted records in raw form under any circumstances.