What the July 2010 storms taught Milwaukee homes about water

What happened in July 2010

Two flash-flood episodes in one week flooded basements and streets across the city.

In July 2010 two flash-flood episodes came within a week of each other. The National Weather Service Milwaukee/Sullivan office recorded up to 7.5 inches of rain in two hours on July 22. The rain was too much for the streets and the sewers at once, and basements filled through floor drains, window wells and the joints in their walls.

The city received at least 2,000 calls about sewer backups into basements. The Milwaukee Metropolitan Sewerage District reported a large combined sewer overflow that month. The events are documented, and they are the main local reason that a basement is treated as the first place to plan for.

Why the basement took the water first

A basement sits at the lowest point of a house, so it fills before any upper floor is reached.

Water finds the lowest point. A basement is the lowest room in most houses, and it takes water from the floor drain when the sewer is full, from the window well when the street overflows and from the joints in the foundation when the ground is saturated. The upper floors stayed dry in many houses that flooded below.

The pattern shows what a homeowner should check: the floor drain, the window wells, the sump, the foundation joints and the stored contents on the lowest shelf. Those are the places the water found first, and they are the places to look before the next storm.

• The floor drain and its connection to the sewer
• The window wells and their covers
• The sump pit and its discharge
• The joints between the wall and the floor
• The stored contents on the lowest shelf

What a sewer backup is and why it is different

A sewer backup carries waste, so it is a contaminated loss with a stricter sequence than clean water.

Water that comes up from a sewer line is not clean. It can carry waste, bacteria and debris, and it must be removed, cleaned and disinfected in a stricter sequence than a supply leak. Porous material that held the water, such as carpet, pad, insulation and lower drywall, usually has to come out.

A basement that is cleaned but not dried can grow mould. A basement that is dried but not cleaned keeps the contamination. The sequence is therefore: protect, extract, remove, clean and disinfect, and dry to readings.

What the insurance question looked like

Water that backs up from a sewer is often not treated as flood water, so the policy wording decides the claim.

A fact-check review dated November 16, 2010 found that water backing up from sewers into basements does not count as flooding under federal flood-insurance definitions, so that damage was generally not covered by that flood policy. That is a review of the definitions, not a statement about any particular policy, and a homeowner should check the wording of your own policy.

The same question returns with each big storm. A local television news report from December 2025 described insurance denials tied to the August floods, and it said the state's Office of the Commissioner of Insurance investigates such disputes. The homeowner's file is the basis for any answer to that question.

• Read the definition of flood in the policy
• Ask in writing whether sewer backup is covered
• Ask whether a rider or separate cover applies
• Keep the scope that says where the water came from
• Use the regulator's complaint route if a denial is not explained

What the city's history means for a repair plan

A repair plan starts with the lower level, the drain and the pump, and it is written before the next storm season.

A homeowner in Milwaukee who has had a basement loss can plan the next repair from the same list the crews use: the floor drain, the backwater valve where one is fitted, the sump and its discharge, the window wells and the stored contents. The plan is written down, and a plumber or contractor can price each item from the list.

A plan written early is also the record an insurer will ask about. It shows the homeowner took reasonable steps, and it makes the next loss easier to explain.

What to do before the next storm season

Test the pump, clear the drains and photograph the lower level before the first heavy storm.

Before each storm season, test the sump by pouring water into the pit until it runs. Check the discharge line. Pour a bucket of water into each floor drain to confirm it drains. Clear the window wells and check their covers. Photograph the lower level as it is, with the date, so that any later loss can be shown against it.

Keep the photographs and the test dates with the house papers. They are the record of care that the insurer will want to see.

• Test the sump and check its discharge
• Pour water into each floor drain
• Clear and check each window well
• Photograph the lower level with the date
• Keep the test dates with the house papers

Why this line answers at any hour

Storms arrive at any hour, so the first call needs to be answered at once.

The July 2010 flash floods came quickly, and a basement can fill faster than a homeowner can reach the panel. The line is answered 24/7, and the dispatcher asks the first questions so that the crew is sent with the facts it needs.

The first steps are simple: keep people out of the water, switch off power to the lower level at the panel if it is safe, and photograph the water line before anything moves.

What the storms showed about the lower level

The lower level is the first to flood, so it is the first place a homeowner should prepare.

The July 2010 storms showed that a lower level can fill while the upper floors stay dry. The water finds the lowest point, and the basement is that point. A homeowner who wants to prepare should start with the lower level, the drains that serve it and the equipment in it.

The record of those storms is also a reminder that a basement with stored contents loses those contents first. Keeping the lowest shelves clear and the valuables above the floor line is one of the simplest protections.

• The lowest room fills first in a storm
• The drains and pump on the lower level matter most
• Stored contents on the floor are lost first
• Valuables kept above the floor line
• A record of what is stored on the lower level

What to measure now

Measure the height of the lowest floor and the equipment, so a later storm can be compared with the house as it was.

A homeowner can measure the height of the lowest finished floor above the outside ground, and the height of the furnace, the water heater and the electrical panel above the lower floor. Photograph the foundation openings and any window well with its cover.

Keep the measurements with the house papers. A later loss can then be compared with the house as it was, and the crew and the insurer have a fixed reference.

How the storms changed the way losses are handled

The storms made the sewer backup a recognised contaminated loss, with its own sequence of protection, removal and cleaning.

Sewer water is handled differently from clean water. It needs protection for the crew, removal of porous material and disinfection of hard surfaces before drying. The sequence is recorded so the homeowner can check each step.

The homeowner's part is to keep the record of the first hour and to ask in writing which part of the policy covers sewer water. Both help the crew and the claim.

• Protection for the crew and the homeowner
• Removal of porous material that held the water
• Disinfection of hard surfaces
• Drying to readings after cleaning
• A written record of each step