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Methodology and data sources

Sewer Line Record is an independent reference built on public records and published sources. It is not an inspection, and nothing here states that a specific sewer line is failing, safe or code-compliant. This page documents where every figure on the site comes from: the datasets, the queries, how values are weighted, and the known holes in each source.

Illustrated cutaway of a sewer lateral running from a house to the main under the street — Illustration: a sewer lateral running from the house, through layered soil, to the city main under the street. The survey describes the layers; it does not describe the pipe.

Soil data: USDA NRCS Soil Survey (SSURGO)

Every soil figure comes from the USDA Natural Resources Conservation Service's SSURGO database, queried live through Soil Data Access. It is public, free, and the same dataset engineers use for a desk review of buried-utility conditions. It is a survey of map units, not of individual lots: a map unit is the smallest area the survey delineates, typically a few acres, and it names the soil series found there with their measured properties.

The fields we read, and where they live

Corrosion risk, uncoated steel and concrete (component.corsteel, component.corcon): the survey's own Low/Moderate/High ratings, taken from the dominant major component of the map unit under the address. Class definitions are in the USDA NRCS Soil Survey Manual, ch. 3 — risk of corrosion and shrink-swell (LEP) classes. These columns live on component, not muaggatt; querying the wrong table returns an error that does not say which column was wrong.
Linear extensibility (shrink-swell) (chorizon.lep_r): for each major component we take every horizon from 0 to 152 cm and compute a thickness-weighted mean; components combine by their mapped percentage; map units combine by intersected area. Classes: low under 3%, moderate to 6%, high to 9%, very high above.
Clay content (chorizon.claytotal_r): weighted the same way; it is the ingredient behind shrink-swell.
Water table minimum depth and drainage class (muaggatt.wtdepannmin, component.drainagecl): map-unit aggregate and dominant-component value respectively, with the range reported when components disagree.

The urban hole, and what we do about it

Map units named plainly “Urban land” carry no measured properties, and sewer laterals are by definition in built-up areas, so this site hits the hole more often than our rural septic sibling. When the unit under an address has no data we widen to a 400 m box, then 800, 1,600 and 3,200, and stop at the first radius where at least 25% of the area has data. The result is labelled a neighborhood estimate with the radius and the data share, and it is never presented as an address-level reading.

Known limits

The survey describes the mapped soil, not your pipe. A PVC lateral in aggressive soil can be fine; a cast-iron one in gentle soil can be rotted through from the inside. Camera footage is the authority for a single line.
The corrosion ratings apply to the materials named: uncoated steel (read: iron-family pipe) and concrete. Clay tile, Orangeburg and plastic pipe fail by other mechanisms — movement, load, root intrusion — not rust.
Geocoding uses the US Census geocoder, then OpenStreetMap Nominatim as a fallback. A failed geocode is reported as a failure, never as a soil result.
SSURGO is updated roughly yearly. A geotechnical report and a camera inspection are the authority for one lot.

We ran it on these addresses

Validation run of 2026-08-31: real addresses chosen to span the corrosion and shrink-swell range. Reproducible with the lookup on the home page.

Address	Precision	Map unit	Steel	Concrete	Shrink-swell	LEP %	Clay %
815 W Mistletoe Ave, San Antonio, TX 78212	address	Austin silty clay, 2 to 5 percent slopes, moderately eroded	High	Low	moderate	4.85	45
7400 E 29th Ave, Denver, CO 80238	address	Urban land-Elyria-Racas complex, 0 to 3 percent slopes	Moderate	Low	moderate	4.23	29.93
4747 SE Woodstock Blvd, Portland, OR 97206	address	Urban land-Latourell complex, 0 to 3 percent slopes	Low	Moderate	low	1.5	16.88
1500 Marilla St, Dallas, TX 75201	neighborhood (1600 m)	Houston Black-Urban land complex, 0 to 4 percent slopes	—	—	very high	9.52	47.3
2100 Snelling Ave N, Roseville, MN 55113	neighborhood (400 m)	Urban land-Hayden-Kingsley complex, 3 to 15 percent slopes	—	—	low	2.6	17.46
1050 E Piedmont Ave NE, Atlanta, GA 30324	neighborhood (400 m)	Urban land-Cecil complex, 2 to 10 percent slopes, moderately eroded	—	—	low	1.5	33.05

Who-pays rules: municipal code

There is no national dataset of lateral responsibility, so our who-pays table is hand-built: one row per city, each citing the municipal code section or the city utility's own published rule it comes from, linked on the row. A city we could not verify does not get a row. Rules change; every row carries the date we checked it.

Cost figures

Every price range on this site is quoted from a named, dated, published source — national cost guides and, where they exist, city fee schedules — and linked at the point of use. No city or national “average” is ever invented, and pipe-material history (what Orangeburg is, when cast iron was common) is cited to published sources, not asserted.

Search and demand data

Page types and their order come from a 377-keyword research corpus pulled 2026-08-31 (Google Ads volume and bids). The largest cluster, “sewer line repair near me”, is deliberately not the first thing built; the cost, method and who-pays questions a homeowner asks while holding a quote are.

How this site makes money

This site may be compensated when homeowners who ask to be contacted are referred to a service provider. Referrals happen only with your consent.