Short answer
This site's local numbers come from public sources: the U.S. Census American Community Survey for housing age, the USDA NRCS soil survey for drainage and estimated water-table depth, NOAA climate normals for rainfall, FEMA's flood maps and the National Weather Service for the 2026 flood. Soil and flood figures come from random points sampled inside each town's Census boundary.
Every local number on this site can be checked against a public source. This page lists the sources, explains how each figure was produced, and compares Anderson with 12 towns around it.
Anderson and nearby towns
| Town | Population | Median year built | Homes built before 1940 | Land rated very limited for basements | Poorly drained soils | Est. water table within ~1 ft | Est. within ~3 ft | Annual rainfall |
|---|---|---|---|---|---|---|---|---|
| Anderson, IN | 55,367 | 1961 | 24% | 71% | 56% | 56% | 69% | 43.3” |
| Elwood, IN | 8,356 | 1950 | 40% | 92% | 78% | 78% | 92% | 42.5” |
| Pendleton, IN | 5,321 | 1990 | 20% | 80% | 72% | 72% | 78% | 42.1” |
| Alexandria, IN | 5,155 | 1962 | 20% | 68% | 50% | 50% | 70% | 42.5” |
| Fortville, IN | 4,976 | 1982 | 15% | 100% | 100% | 100% | 100% | 42.1” |
| Lapel, IN | 2,668 | 1975 | 27% | 100% | 98% | 98% | 100% | 42.1” |
| Ingalls, IN | 2,512 | 2000 | 7% | 72% | 60% | 60% | 72% | 42.1” |
| Chesterfield, IN | 2,489 | 1959 | 14% | 40% | 20% | 18% | 32% | 43.6” |
| Middletown, IN | 2,235 | 1955 | 32% | 24% | 10% | 10% | 24% | 43.6” |
| Edgewood, IN | 2,121 | 1956 | 16% | 98% | 56% | 56% | 100% | 43.8” |
| Frankton, IN | 1,658 | 1967 | 20% | 92% | 58% | 58% | 86% | 42.5” |
| Daleville, IN | 1,584 | 1964 | 17% | 62% | 22% | 48% | 74% | 43.6” |
| Summitville, IN | 1,104 | 1958 | 38% | 100% | 56% | 56% | 100% | 42.5” |
Housing: U.S. Census ACS 2024 5-year estimates. Soils: USDA NRCS soil survey, shares of random points inside each town’s Census boundary (120 for Anderson, 50 for the others). “Poorly drained” combines the somewhat poorly, poorly and very poorly drained classes. Rainfall: NOAA 1991-2020 normals from the reporting station nearest each town. For Anderson that’s the Water Works station; the Anderson 1 N station reports 43.8 inches, which is the figure used elsewhere on this site.
What stands out
The wettest ground is south and west, toward Fortville, Lapel and Pendleton. Every or nearly every sampled point in Fortville and Lapel is poorly drained, with an estimated seasonal water table within about a foot.
Elwood combines wet ground with the oldest housing. Its median home dates to 1950 and 40% of homes were built before 1940, on land where 78% of sampled points have an estimated water table within about a foot (Census ACS 2024; USDA NRCS). See Elwood and Lapel, the wettest sample.
Chesterfield and Middletown are the exceptions. Only 24% of Middletown’s sampled land and 40% of Chesterfield’s is rated very limited for basements (USDA NRCS). On that better-drained ground, roof water, grading and old drains are more likely causes than the water table.
Newer towns sit on the same wet ground. Ingalls (median year built 2000) and Pendleton (1990) have newer homes, but their soils are mostly wet till. Newer basements usually have footing drains and a sump, and they depend on both working.
Daleville’s soils are least certain. Much of its sampled land is mapped as “urban land” complexes, where the soil survey describes disturbed ground less precisely.
How each number was produced
Housing age (U.S. Census)
From the American Community Survey 2024 5-year estimates for each Census place: population (table B01003), median year built (B25035), and the share of homes in each year-built band (B25034). Small towns have wide margins of error.
Soils and the estimated water table (USDA NRCS)
For each town, we placed random points inside the Census boundary and looked up the soil map unit at each point through the USDA NRCS Soil Data Access service. For each map unit we used the published ratings:
- Dwellings with basements: the dominant-condition rating (not limited, somewhat limited, very limited).
- Drainage class: from well drained to very poorly drained.
- Water table (estimated): the shallowest depth to a seasonal saturated zone, counted as within about 1 foot (30 cm) or 3 feet (91 cm). Points with no rating count as not shallow, which keeps the shares conservative.
Flood zones (FEMA)
120 random points inside Anderson’s city boundary, checked against FEMA’s National Flood Hazard Layer in October 2026. See flood zones.
The 2026 flood (National Weather Service)
The crest at Anderson and the rainfall totals come from the National Weather Service Indianapolis summary “Record Flooding of August 2026”. The city’s flood stage comes from the City of Anderson’s flood information page.
Sewers (federal court records)
The combined sewer details come from the consent decree case United States v. City of Anderson (S.D. Indiana, 1:02-cv-01103) and its 2010 modification filing, as published by the U.S. EPA.
Prices
Cost ranges come from established U.S. cost guides, listed on the cost page. They’re ranges, not quotes.
Limits of this data
- Water-table figures are estimates, not measurements. The soil survey estimates depth to a seasonal saturated zone for each mapped soil. We didn’t find groundwater measurements at a useful neighborhood scale.
- “Very limited” is a building-suitability rating. It describes how hard the ground is to build a basement on, mostly because of wetness. It doesn’t mean every basement there leaks.
- Soil maps can’t show every lot. Fill, grading and old drainage change conditions property by property.
- Census figures for small towns carry wide margins of error.
- Rainfall normals are 30-year averages. August 2026 showed how far a single week can exceed them.