Sioux Falls Mold Recovery Guide: Basements, Winter Condensation and Storm Leaks

A free recovery and process guide for homeowners in Sioux Falls and the rest of Minnehaha County, from Get Mold Remediation Pros.

Mold in a cold, dry-summer city

Sioux Falls summers are less humid than the South's; NOAA counts about 232 hours a year with the wet-bulb above 73°F. But mold still finds water here, mostly in basements, behind frosty windows and after storms. Deep frost, with a 50-year frost depth of 102 inches, drives moisture through foundations in spring, and severe storms, like the September 10–11, 2019 winds of 80 to 100 mph that damaged buildings in the city, open roofs and walls to rain. This guide covers recovery and prevention.

Step 1: Find the water

Common sources in Sioux Falls homes:

basement leaks during spring thaw and heavy rain;
condensation on cold windows and rim joists in winter;
ice dams that push water into ceilings and walls;
plumbing leaks;
a humidifier set too high in cold weather.

Stop the source before you clean.

Step 2: Dry the area

Use fans and dehumidifiers. In winter, keep the house heated while drying.

Step 3: Clean or call

A small patch on a hard surface can often be cleaned by a homeowner wearing gloves, eye protection and a respirator. Large areas, finished basements with mold inside walls, or mold in ducts need a professional. Discard porous materials that stay moldy.

Step 4: Storm damage and insurance

After a storm, document first. South Dakota's Division of Insurance says insurers must respond to all claim communications within 30 days, though that does not oblige them to pay within that time. It advises photographing damage before repairs where possible, keeping all receipts for temporary repairs, and not making permanent repairs before contacting the insurer. Covering a roof opening quickly is a temporary repair that also prevents mold.

Step 5: Hiring a remediation company

Ask for a written scope: affected areas, containment, removal, drying, cleaning and how completion will be shown. Ask how they will address the moisture source. Get more than one quote.

Winter condensation

Frost and water on the inside of windows, and damp rim joists, mean indoor humidity is too high for the outdoor temperature. Lower the humidifier setting on the coldest days, run bath fans, and ask an HVAC contractor about ventilation.

Prevention

Keep downspouts extended and soil sloped away from the foundation.
Test the sump pump each spring.
Insulate and air-seal rim joists.
Watch basement humidity in summer and run a dehumidifier.

Records

Keep photos, receipts, moisture readings and remediation reports.

Finished basements

Mold in a finished basement often hides behind drywall and under carpet. If you smell mustiness, look at the bottom of walls and inside closets on exterior walls. Ask a remediation company whether they can check wall cavities with a moisture meter before opening walls.

Sources for this guide

In an average year at Sioux Falls, NOAA counts about 232 hours with the wet-bulb temperature above 73°F and about 892 hours above 67°F. Source: NOAA NCEI Engineering Weather Data (Sioux Falls, SD)
South Dakota's Division of Insurance says insurance companies must respond to all claim communications within 30 days, though that does not oblige them to pay within that time. It advises photographing damage before repairs where possible, keeping all receipts for temporary repairs, and not making permanent repairs before contacting the insurer. Source: South Dakota Division of Insurance, Claims Process
NOAA's engineering weather data for Sioux Falls lists an average of 75 freeze-thaw cycles a year, a 50-year frost depth of 102 inches and a 50-year ground snow load of 40 pounds per square foot. Source: NOAA NCEI Engineering Weather Data (Sioux Falls, SD)
On the night of September 10–11, 2019, a line of severe thunderstorms brought straight-line winds of 80 to 100 mph and considerable tree damage, and three brief EF-2 tornadoes touched down within Sioux Falls, damaging the Avera Health complex along 69th Street and the 41st Street commercial corridor. Source: NWS Sioux Falls, Sioux Falls Tornadoes – September 10, 2019

Sources checked 2026-10-26. Every cost figure on this page comes from a source named above; fees and rules change, so confirm current amounts with the office that sets them before you budget.