Basement Flooding in Macomb, Oakland and Wayne Counties: What the Public Data Shows

Updated November 2026. Compiled by Mansour’s Innovations from public FEMA, NOAA and State of Michigan records.

Most basement flooding in Southeast Michigan never shows up in a single official count. It shows up in pieces: flood insurance claims, federal aid registrations, National Weather Service storm reports and sewer discharge reports filed with the state.

This guide puts those pieces side by side for Macomb, Oakland and Wayne counties from 2014 through 2026, with flood insurance claims back to 1978. Each number names its source, and the agency links are under “How we built this.”

Key findings

• Since 2014, three storms have brought federal disaster declarations covering all three counties: August 2014, June 2021 and August 2023. (FEMA disaster declarations)
• After each one, about 99,000 to 143,000 households in the three counties registered for FEMA aid: 127,390 in 2014, 99,162 in 2021 and 142,574 in 2023. (FEMA Housing Assistance data, as of Nov. 6, 2026)
• Flood insurance claims for the same storms numbered in the hundreds: 543, 151 and 138. (FEMA NFIP claims, as of Sept. 8, 2026)
• Fewer than 1 in 200 homes here has federal flood insurance. FEMA counts 5,813 residential flood policies for about 1.38 million residential buildings in the three counties, or 0.42%. (FEMA NFIP penetration rates, as of Aug. 3, 2026)
• Insured flood losses here usually involve a basement. Since 2014, 89% of claims with a recorded foundation type were for a building with a finished or unfinished basement. (FEMA NFIP claims)
• Flooding doesn’t stop at the flood map. Since 2014, 38% of claims with a recorded flood zone were for buildings rated outside FEMA’s high-risk zones. (FEMA NFIP claims)
• Sewer discharges are routine in wet weather. In the state’s list, discharges in the three counties started on 92 to 122 days a year from 2014 through 2025. About three in four of the 4,422 reports filed since January 2014 came from Wayne County. (Michigan EGLE MiEnviro list, as of Nov. 6, 2026)

The big storms, side by side

Storm	Rain (NOAA)	Federal declaration (FEMA)	FEMA aid registrations	Flood insurance claims	Sewer discharges that started (EGLE)
Aug. 11-13, 2014	4 to 6 in. in about 4 hours	DR-4195	127,390	543	126
Apr. 29-May 2, 2019	2 to 4 in. in about 4 hours along I-94	None	n/a	153	82
June 25-27, 2021	3 to 5 in., locally 6 to 8; 8.19 in. in Grosse Pointe Park	DR-4607	99,162	151	112
Aug. 23-26, 2023	Many 3 to 5 in. totals overnight; 7.36 in. in Belleville	DR-4757	142,574	138	90
Apr. 2-3, 2025	2 to 3 in. in 24 hours in parts of Metro Detroit	None	n/a	23	98
July 28-30, 2025	2.68 in. in 2.5 hours at Detroit Metro Airport	None	n/a	9	52

Sources: rain from NOAA Storm Events Database narratives; declarations from FEMA; aid registrations (valid registrations by homeowners and renters in the three counties) from FEMA Housing Assistance data, as of Nov. 6, 2026; flood insurance claims with a loss date in each window from FEMA NFIP claims, as of Sept. 8, 2026; sewer discharge records with a start date in each window from the Michigan EGLE MiEnviro list, as of Nov. 6, 2026.

August 2014. NOAA’s summary says about 75,000 homes and businesses were damaged, more than 3,000 of them with major damage, and that city sewer pumps “were overwhelmed by the torrential rainfall.” FEMA declared the disaster for all three counties on Sept. 25, 2014. (NOAA Storm Events Database; FEMA disaster declarations)

May 2019. There was no federal declaration, but NOAA records about 5,000 homes with basement flooding, about 1,000 of them with major damage, with Dearborn Heights hardest hit. (NOAA Storm Events Database; FEMA disaster declarations)

June 2021. NOAA records almost 15,000 homes with major flood damage and close to 6,000 with minor damage in Wayne County. FEMA declared the disaster for Wayne on July 15, 2021, and added Macomb and Oakland on Sept. 24, 2021. (NOAA Storm Events Database; FEMA disaster declarations)

The Great Lakes Water Authority (GLWA) commissioned an independent investigation. Michigan Public reported that it found pump failures likely made the flooding worse, but the system’s capacity to carry water, not pumping, was the main cause, and more pumping would not have meaningfully reduced basement backups. (Michigan Public, June 24, 2022)

August 2023. The early-morning flooding hit western Wayne County hardest, including Canton and the Detroit Metro Airport area. Storms that evening cut power to close to 500,000 customers in southern Lower Michigan. FEMA declared the disaster on Feb. 8, 2024. The declaration covers severe storms, tornadoes and flooding, so its aid registrations include wind damage as well as water. (NOAA Storm Events Database; FEMA disaster declarations)

Since 2023. NOAA lists smaller floods, including 3 to 5 inches over part of central Macomb County with water rescues on June 18, 2025, and a local emergency in the Village of Holly (Oakland County) on April 4, 2026, after flooding damaged pumps at its wastewater plant. No federal declaration since August 2023 has included Macomb, Oakland or Wayne. Michigan’s latest, DR-4925 for the April 10-21, 2026 storms, covers 37 counties, including neighboring Washtenaw, but not these three. (NOAA Storm Events Database; FEMA disaster declarations, checked Nov. 6, 2026)

Year by year, 2014-2026

Year	Flood insurance claims (FEMA)	NOAA flood entries	Sewer discharge reports (EGLE)	Days a sewer discharge started (EGLE)
2014	590	6	410	110
2015	18	0	311	92
2016	77	8	332	98
2017	19	3	313	98
2018	56	3	440	118
2019	250	22	380	122
2020	58	45	374	105
2021	234	14	452	118
2022	27	0	238	95
2023	180	2	284	98
2024	50	3	370	110
2025	41	7	246	102
2026 (partial)	21	1	272	104

Sources: FEMA NFIP claims by year of loss, as of Sept. 8, 2026; NOAA Storm Events Database flash flood, flood and lakeshore flood entries, Michigan rows through July 2026; Michigan EGLE MiEnviro list, as of Nov. 6, 2026. All three counties combined.

Before 2014, the biggest claim years were 1985 (666 claims) and 1986 (620). 2014 ranks third since 1978. (FEMA NFIP claims)

EGLE’s list also includes reports from years before its MiEnviro portal opened. We have not checked the 2014-2020 counts against EGLE’s older annual reports, so compare early years with care.

FEMA aid registrations after declared storms

When a storm gets a federal declaration, households in the designated counties can register for FEMA aid whether or not they have flood insurance. That makes registrations a much wider, if still partial, view of storm damage.

County	Aug. 2014 (DR-4195)	June 2021 (DR-4607)	Aug. 2023 (DR-4757)
Wayne	97,548	94,357	120,070
Oakland	18,837	2,189	11,265
Macomb	11,005	2,616	11,239
All three	127,390	99,162	142,574

Source: FEMA Housing Assistance Program Data, valid registrations by homeowners and renters, by FEMA’s county label, as of Nov. 6, 2026.

FEMA inspectors found damage at the homes of 70,788 homeowners who registered after the 2014 storm, 39,561 after 2021 and 77,199 after 2023. (FEMA Housing Assistance data, owners)

Storm	ZIP with the most homeowner registrations	Leading Macomb ZIP	Leading Oakland ZIP
Aug. 2014	48126 Dearborn: 4,336	48089 Warren: 1,302	48237 Oak Park: 2,929
June 2021	48126 Dearborn: 6,260	48021 Eastpointe: 482	48076 Southfield, Lathrup Village: 193
Aug. 2023	48227 Detroit: 4,683	48021 Eastpointe: 1,887	48076 Southfield, Lathrup Village: 1,104

Source: FEMA Housing Assistance Program Data, owners, valid registrations, as of Nov. 6, 2026. Place names are the ones registrants entered. Each ZIP code is counted with the county that holds most of its registrations.

In 2014, Detroit’s 48227 (4,260) and 48228 (4,217) came next after Dearborn’s 48126. In 2023, all eight ZIP codes with the most homeowner registrations were in Detroit. (FEMA Housing Assistance data, owners)

Read these numbers with care. A registration is a request for help, not a confirmed basement flood, and the 2021 and 2023 declarations also covered tornado and wind damage. NOAA’s summary of the June 2021 storm names Wayne and Washtenaw as the hardest-hit counties. (FEMA disaster declarations; NOAA Storm Events Database)

Flood insurance: few policies, mostly basements

County	Flood insurance claims, 1978-2026	Claims, 2014-2026	Residential flood policies (Aug. 2026)	Share of homes insured
Wayne	2,892	1,152	3,357	0.52%
Macomb	1,437	281	1,360	0.46%
Oakland	582	188	1,096	0.26%
All three	4,911	1,621	5,813	0.42%

Sources: claims from FEMA NFIP claims, as of Sept. 8, 2026 (2026 is a partial year); policies and shares from FEMA NFIP Residential Penetration Rates, as of Aug. 3, 2026, which compare residential policies with FEMA’s count of residential buildings. Private flood insurance is not counted.

Only 17,988 of the three counties’ 1,376,481 residential buildings are in FEMA’s high-risk flood zones, but those buildings hold about 71% of the residential policies (4,147). About 23% of homes in those zones carry a policy. (FEMA NFIP penetration rates)

What the claims since 2014 show

Measure	Share	Claims
Building had a finished or unfinished basement	89%	1,156 of 1,302 with a foundation type recorded
Single-family home	90%	1,457 of 1,621
Cause: accumulation of rainfall or snowmelt	61%	966 of 1,583 with a cause recorded
Cause: stream, river or lake overflow	25%	394 of 1,583
Rated outside FEMA’s high-risk zones (X, B or C)	38%	609 of 1,615 with a zone recorded
Claim resulted in a payment	67%	1,091 of 1,621

Source: FEMA NFIP claims, loss years 2014-2026, as of Sept. 8, 2026.

Where the claims are

ZIP	Communities on the claims	County	Claims, 2014-2026	Rated in a high-risk zone
48125	Dearborn Heights	Wayne	331	95%
48215	Detroit	Wayne	249	62%
48229	Ecorse	Wayne	90	71%
48173	Gibraltar, Brownstown Twp.	Wayne	66	85%
48124	Dearborn	Wayne	65	75%
48047	Chesterfield Twp., New Baltimore	Macomb	60	75%
48045	Harrison Twp.	Macomb	50	86%
48067	Royal Oak	Oakland	19	0%
48083	Troy	Oakland	19	84%

Source: FEMA NFIP claims (reported ZIP code and NFIP community on each claim; zone share among claims with a recorded rating zone), as of Sept. 8, 2026. The first seven rows are the top seven ZIP codes in the three counties; 48067 and 48083 lead Oakland County.

Royal Oak’s 48067 is different: none of its claims since 2014 was rated in a high-risk zone. The same is true of Detroit’s 48227, 48228 and 48235. (FEMA NFIP claims)

What a flood policy covers in a basement

FEMA’s standard flood policy excludes water that backs up through sewers or drains unless there is a flood in the area and the flood caused the backup. In a basement, it covers only a short list of items, such as furnaces, water heaters and sump pumps, plus washers and dryers if the policy includes contents coverage. (FEMA Standard Flood Insurance Policy, Dwelling Form)

What NOAA’s storm records show

County	Flash flood	Flood	Lakeshore flood	All flood entries
Wayne	17	20	22	59
Macomb	13	14	10	37
Oakland	12	6	0	18
All three	42	40	32	114

Source: NOAA Storm Events Database, January 2014 through July 2026.

The 114 entries fall on 61 different dates. Flash floods were recorded on 25 dates, in every year from 2014 to 2025 except 2015 and 2022. (NOAA Storm Events Database)

The busiest stretch, 2019-2020, had 67 entries, and 42 of them were lakeshore floods or month-long high-water floods, not storm runoff. NOAA says record-high Great Lakes water levels caused lakeshore flooding from late April to November 2019. In summer 2020, Lake St. Clair stayed above its flood elevation for months, flooding shoreline areas in Macomb and Wayne counties. (NOAA Storm Events Database)

NOAA entries record reported events, not every flooded home. A storm that floods basements across a city can appear as a single county-level entry.

Sewer discharges reported to the state

When heavy rain overloads the sewers, some systems release untreated or partly treated sewage into rivers, lakes and drains. Operators report each discharge to Michigan’s Department of Environment, Great Lakes, and Energy (EGLE), which lists them in its MiEnviro portal.

County	Reports, Jan. 2014-Nov. 2026	Discharge records	Most common type
Wayne	3,406	10,089	Combined sewer overflow
Oakland	631	656	Sanitary sewer overflow
Macomb	386	404	Retention treatment basin discharge
All three	4,422	11,149	Combined sewer overflow (70% of records)

Source: Michigan EGLE MiEnviro CSO/SSO list, as of Nov. 6, 2026. A record is one outfall or discharge point within a report. One report covers two counties, so the county rows add up to 4,423 reports.

Retention treatment basins hold combined sewage during storms and partly treat it before release.

Discharges cluster on the same dates as basement flooding: 126 discharge records started during the August 2014 storm and 112 during the June 2021 storm. (EGLE MiEnviro list)

In parts of the region, storm water and sewage share the same pipes. These combined systems serve Detroit and several neighboring communities, and parts of south Oakland County in the George W. Kuhn drainage district. When those pipes are full, water can push back up through basement floor drains. (City of Detroit Water and Sewerage Department; Oakland County Water Resources Commissioner)

Programs that help with sewer backups

These are the programs we found on official city pages as of Nov. 6, 2026. Rules and funding change, so check with your city before you plan any work.

Program	Who it serves	What it covers	Status we found
Detroit Basement Backup Protection Program (DWSD)	Owners and landlords of occupied houses and duplexes in 11 Detroit neighborhoods	A backwater valve and/or a sump pump	Applications for Phases 1 and 2 are closed; the city says they will reopen if more funding comes
Detroit Private Sewer Repair Program (CDBG-DR)	Income-eligible owners in listed Detroit neighborhoods with damage tied to the June 2021 flood	Sewer camera inspection, private sewer repair, downspout disconnection and backwater valves; sump pumps in rare cases	The city’s FAQ says applications are taken until funding runs out but still describes intake through 2024, so call the city
Royal Oak RENO program	Royal Oak owners of single-family homes, duplexes, townhomes and condos	Waives city permit and inspection fees for approved work, including backwater check valves and sump or ejector pumps; does not cover contractor, labor or material costs	Apply with your building permit, before work starts; the city says approvals depend on available funding

Sources: City of Detroit Water and Sewerage Department; City of Detroit CDBG-DR program page; City of Royal Oak RENO program pages. Read Nov. 6, 2026.

Footing drains. We did not find an active, funded footing drain disconnection program in the three counties. Grosse Pointe Park tells residents that footing drains tied to the sanitary sewer must be disconnected before a sanitary backflow device is installed. (City of Grosse Pointe Park)

Permits. A backwater valve usually needs a plumbing permit. Dearborn, St. Clair Shores and Warren list one on their plumbing permit applications, Royal Oak lists one in its plumbing fee schedule, and Grosse Pointe Park requires a permit for any sewer lateral work. (City permit forms and fee schedules)

Public flood projects

These public projects don’t pay for work at your house:

• North Branch Ecorse Creek drain work (Wayne County): clearing and bank repair approved in April 2023 as a two-year project, for Dearborn Heights and eight neighboring communities. (Wayne County Commission)
• City of Dearborn: flap gates and pumps that act as backflow preventers for about 13,600 residents, plus sewer separation planning, announced as underway in September 2025. (City of Dearborn)

What the data can’t tell you

• No dataset counts every flooded basement. Flood insurance claims miss the more than 99% of homes without a federal flood policy. (FEMA NFIP penetration rates) FEMA aid registrations exist only for declared storms and include wind damage. NOAA entries are summaries, and EGLE reports describe sewers, not houses.
• Groundwater seepage is almost invisible in these records. A slow leak through a wall crack is a different problem from a sewer backup or overland flooding, and none of these datasets track it.
• Data dates differ. Flood insurance claims are as of Sept. 8, 2026, and recent claims can take months to appear. NOAA records run through July 2026. FEMA aid registrations and EGLE reports are as of Nov. 6, 2026.
• The source data has small errors. One EGLE report lists an impossible discharge volume, so we used counts and dates, not volumes. Fewer than 0.2% of homeowner aid registrations here carry a county that doesn’t match their ZIP code; we kept FEMA’s county labels as published. (EGLE MiEnviro list; our check of FEMA Housing Assistance data)

What homeowners can do

1. Know which water you’re dealing with. Water up through a floor drain during a storm is usually a sewer backup. Water through a wall crack or at the floor edge is groundwater. Our sewer backup guide explains the difference.
2. If sewage has come up your floor drain, ask about a backwater valve. It usually needs a plumbing permit, and Grosse Pointe Park says footing drains tied to the sanitary sewer must be disconnected first. See backwater valves. Camera inspections show the condition of your sewer line before any work is planned. A sewer camera inspection is $350, and that includes locating the line, a saved video of the pipe and a written report.
3. Plan for power outages. The August 2023 storms cut power to close to 500,000 customers in southern Lower Michigan. (NOAA Storm Events Database) Look at a battery backup sump pump and test your sump pump before storm season.
4. Move roof water away from the house. Detroit’s Private Sewer Repair Program includes downspout disconnection. See yard drainage and downspouts.
5. Check your insurance before the next storm. Ask your agent about water backup coverage and whether flood insurance makes sense for your address. Our insurance guide covers the basics.
6. After a backup, act fast. Send written notice to the agency that runs your sewer within 45 days (MCL 691.1419), and take photos before you clean up. Our first 24 hours guide walks through the steps, and cleanup help is on our flood restoration page.

For seepage through walls or floors, see interior waterproofing. Our basement flood protection guide and cost guide go further.

Local details are on our Macomb County, Oakland County and Wayne County pages, and on city pages for places that show up in this data: Detroit, Warren, Harrison Township, Chesterfield Township, New Baltimore, Royal Oak, Troy and Grosse Pointe Park.

How we built this

Mansour’s Innovations, a family-owned basement waterproofing, excavation and plumbing contractor in Shelby Township, compiled this guide from public records. We pulled each dataset from the agency on Nov. 6, 2026, kept the records for Macomb, Oakland and Wayne counties, and counted them. We did not adjust any numbers.

• Shares leave out records where that field is blank. For example, 319 of the 1,621 flood insurance claims since 2014 have no foundation type recorded. (FEMA NFIP claims)
• Storm windows: flood insurance claims and sewer discharges are counted by date within the windows shown in the storm table.
• FEMA aid registrations are valid registrations by homeowners and renters, using FEMA’s county labels.
• NOAA entries are one record per county or forecast zone per event. “Dates” are distinct start dates.
• EGLE: a report is one submission, and a discharge record is one outfall or discharge point within a report. We used counts and dates, not volumes, because reported volumes are inconsistent and at least one is an obvious entry error.

Sources (accessed Nov. 6, 2026):

• FEMA (OpenFEMA): NFIP Redacted Claims, v3 (data as of Sept. 8, 2026); Housing Assistance Program Data, Owners, v2 and Renters, v2; Disaster Declarations Summaries, v2; FEMA Web Declaration Areas, v1; NFIP Residential Penetration Rates, v1 (as of Aug. 3, 2026).
• NOAA National Centers for Environmental Information: Storm Events Database, using its bulk data files for 2014-2026 (Michigan rows through July 2026).
• Michigan EGLE: MiEnviro Portal CSO/SSO list and the CSO, SSO and RTB program page.
• Flood insurance rules: FEMA Standard Flood Insurance Policy, Dwelling Form (F-122, October 2021).
• Sewer backup claims: MCL 691.1419 (Public Act 222 of 2001) and the Oakland County Water Resources Commissioner’s basement flooding claim guidance.
• Programs, projects and permits: City of Detroit Basement Backup Protection Program and Private Sewer Repair Program; City of Royal Oak RENO Program and eligible activities; City of Grosse Pointe Park Water/Sewer Systems; Wayne County Commission, April 2023; City of Dearborn, Sept. 25, 2025; plumbing permit applications from Dearborn, St. Clair Shores and Warren, and Royal Oak’s Master Administrative Fee Schedule (effective July 1, 2025).
• News reports: Michigan Public, June 24, 2022 (GLWA’s investigation); Planet Detroit, July 20, 2022 (GLWA’s denial of claims).

This product uses the Federal Emergency Management Agency’s OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency’s website(s).

Suggested citation: Mansour’s Innovations, “Basement Flooding in Macomb, Oakland and Wayne Counties: What the Public Data Shows,” updated November 2026, mansoursinnovations.com. Compiled from FEMA (OpenFEMA), NOAA (NCEI Storm Events Database) and Michigan EGLE (MiEnviro) data.