Plumbing repair · O'Fallon, Missouri

Plumbing repair in O'Fallon, MO

Leak, backed-up drain, no hot water, or a frozen line? The largest share of O'Fallon's homes (31%) was built 1990 to 1999^[1]. Request a licensed plumber who works here. O'Fallon, in St. Charles County — ZIPs 63366, 63368, counts 96,101 residents (2025 estimate)^[2].

Request help

Do you need an emergency plumber?

Answer a few questions to see how fast you need help.

Decision guide

O'Fallon plumbing snapshot: the key figures

Population (2025 est.): 96,101^[2]+5.2% since 2020
County: St. Charles^[2]
Land area: 31.0 sq mi^[3]
Population density: 3,101 / sq mi^[2]^[3]
Decade the most homes date from: 1990 to 1999^[1]31% of housing units
Homes built before 1980: 9%^[1]the lowest share of the 15 St. Louis–area suburbs we cover
Homes built 1980–1999: 41%^[1]2020–2024
Homes built 2010 or later: 20%^[1]the 3rd-highest share of the 15 St. Louis–area suburbs we cover
Winter-storm & freeze days, st. charles zone: 12^[4]2016–2025
Flood & flash-flood reports within 10 mi: 6^[4]6 flash floods, 2016–2025; flood-prone homes need working drainage and backflow prevention
FEMA flood-insurance claims, local ZIPs: 347^[5]63 in the last 10 years; 291 paid
Homes on utility gas heat: 71%^[1]gas piping work usually needs a permit and a licensed installer

Reading the O'Fallon data for plumbing

O'Fallon is one of the fastest-growing St. Louis–metro suburbs tracked here: 96,101 people (2025 estimate), up 5.2% since 2020^[2]. On the map that's 31.0 square miles holding 3,101 residents per square mile, the 6th densest of the suburbs here; it sits entirely in St. Charles County, with ZIP codes 63366, 63368^[3].

With 20% of homes built since 2010 and 9% before 1980^[1], O'Fallon's plumbing runs from brand-new supply lines and fixtures to aging pipe, original valves and water heaters past their rated life.

O'Fallon is split across 2 ZIP codes: 63366 (54% of the city's land), 63368 (30% of the city's land)^[6].

Nearest of the other suburbs we track: Lake St. Louis (3.4 mi W), St. Peters (6.3 mi E) and Wentzville (8.4 mi W)^[3].

9% of O'Fallon's 36,206 housing units predate 1980 and 20% went up in 2010 or later^[1] — the lowest pre-1980 share of the 15 St. Louis–area suburbs we cover; nearby, Lake St. Louis (19%), St. Peters (25%), and Wentzville (10%) predate 1980. New-construction problems are usually fittings, supply lines, water-heater installs and drain slopes, not worn-out pipe.

The biggest single slice — 31% — was built 1990 to 1999, and the median home dates to 2000^[1]. Neighbours from the same era tend to hit the same plumbing problems at the same time.

Freeze risk: the st. charles forecast zone logged 12 winter-storm, ice or hard-freeze days in 2016–2025, including February 2021; the latest was Dec 1, 2025^[4].

Water from the sky is plumbing work too: 6 flood or flash-flood reports within 10 miles over 2016–2025^[4], and FEMA logged 347 flood-insurance claims across O'Fallon's ZIPs^[5]. Homes that take water need working drainage, sump pumps and backflow prevention.

71% of homes heat with utility gas, and 19% of households rent^[1].

Measured against the 15 suburbs on this site, O'Fallon records the lowest pre-1980 housing share (9%)^[1], the 2nd-newest housing (by median year built) (2000, tied with Lake St. Louis)^[1], the 3rd-highest share of homes built since 2010 (20%)^[1], and the 3rd-fewest flood reports nearby (6)^[4].

O'Fallon storm calendar

Within 10 miles of O'Fallon, 2016–2025: 6 flash-flood reports^[4]. Peak: 83% in April, June, and July. Busiest year 2019 (2); 6 of 10 years had none. Busiest month May 2019 (1). Latest: flash-flood report, Jun 4, 2025, 9.5 mi out.

O'Fallon, 2016–2025
Month	Flash flood	Flood & heavy rain	All
Apr	1	–	1
May	1	–	1
Jun	2	–	2
Jul	2	–	2

Darker squares, more reports. NOAA Storm Events Database^[4].

plumbing help in O'Fallon: what to do next

Your request reaches Plumbing repair contractors who serve O'Fallon (ZIP codes 63366, 63368).

Compare plumber quotes PLACEHOLDER
See another plumbing partner PLACEHOLDER

Before you call: before the plumber arrives

The O'Fallon numbers behind this page

How O'Fallon stacks up against the median suburb we cover (median of 15)^[1]^[4]
Measure	O'Fallon	Median of 15	Difference
Built 2010 or later	20%	6%	13 pts higher
Built before 1980	9%	54%	45 pts lower
Built before 1960	3.0%	9.8%	7 pts lower
Flood reports (10 mi)	6	14	8 fewer
Renter-occupied	19%	23%	4 pts lower
Utility-gas heat	71%	69%	2 pts higher
Median year built	2000	1977	23 years newer

Biggest gaps first. Medians are middle values across the St. Louis–area suburbs we cover, drawn from the same sources.

O'Fallon and nearby suburbs, side by side^[4]^[5]^[3]
City	Flood reports	NFIP claims
O'Fallon	6	347
Lake St. Louis 3.4 mi	5	14
St. Peters 6.3 mi	8	534
Wentzville 8.4 mi	5	13
St. Charles 11.2 mi	12	5,630
Chesterfield 11.5 mi	11	321

Flood-insurance claims by ZIP code, since 1979^[5]
ZIP	Claims	Paid	Busiest year
63366	333	$6,971,988	1993 (78)
63368	14	$106,960	1983 (2)

ZIPs extend past city limits.

Most recent flood reports within 10 miles^[4]
Date	Type	Distance
Jun 4, 2025	Flash Flood	9.5 mi
Apr 4, 2025	Flash Flood	8.6 mi
Jul 26, 2022	Flash Flood	7.5 mi
Jun 22, 2020	Flash Flood	5.5 mi
Jul 10, 2019	Flash Flood	2.8 mi
May 6, 2019	Flash Flood	9.5 mi

When O'Fallon's 36,206 housing units were built^[1]
Built	Units	Share	Margin of error
2020 or later	1,346	3.7%	±256
2010 to 2019	5,726	15.8%	±528
2000 to 2009	10,946	30.2%	±761
1990 to 1999	11,382	31.4%	±705
1980 to 1989	3,468	9.6%	±497
1970 to 1979	1,119	3.1%	±308
1960 to 1969	1,150	3.2%	±316
1950 to 1959	666	1.8%	±186
1940 to 1949	123	0.3%	±92
1939 or earlier	280	0.8%	±120

ACS 2020–2024 estimates; margins of error are the Census Bureau's 90% intervals.

O'Fallon housing and households^[1]
Measure	Value
Housing units	36,206
Detached single-family	27,212 (75%)
Occupied homes	35,471
Owner-occupied	28,737 (81%)
Renter-occupied	6,734 (19%)
Median home value	$326,200

ACS 2020–2024 estimates.

How O'Fallon's 35,471 occupied homes are heated^[1]
Main heating fuel	Homes	Share	Margin of error
Utility gas	25,084	70.7%	±744
Electricity	9,557	26.9%	±705
Bottled or tank gas (propane, butane, etc.)	449	1.3%	±141
Fuel oil, kerosene, etc.	119	0.3%	±100
No fuel used	113	0.3%	±91
Other fuel	75	0.2%	±80
Wood	74	0.2%	±77

ZIP code areas covering O'Fallon^[6]
ZIP (ZCTA)	Share of O'Fallon's land	Share of the ZIP inside the city
63366	54%	23%
63368	30%	55%

Dated heat and freeze records for the ST. CHARLES forecast zone: see the county list.

O'Fallon plumbing questions

Are O'Fallon homes likely to have old galvanized pipes?

Only an inspection can say, but age is the clue: 3% were built before 1960 and 9% before 1980^[1].

How often do pipes freeze in O'Fallon?

The record for O'Fallon's forecast zone shows 12 winter-storm or freeze days over 2016–2025, in 7 different years^[4].

Which ZIP codes are covered in O'Fallon?

63366 and 63368^[6], in St. Charles County. Nearby suburbs with their own pages: Lake St. Louis (3.4 mi), St. Peters (6.3 mi), and Wentzville (8.4 mi)^[3].

My O'Fallon home is fairly new — could the plumbing and water heater still be under warranty?

Possibly: 20% of O'Fallon's housing units were built in 2010 or later^[1], the 3rd-highest share of the 15 St. Louis–area suburbs we cover. Check your closing paperwork for warranties before paying for a repair.

Sources

Data pulled Sep 28, 2026. Full citations and method.