Spring in De Smet can flip from melting snow to a fast thunderstorm in hours. If you worry about a damp basement, sump pump failures, or sewer backups, you are not alone. In this guide, you will learn practical steps tailored to De Smet’s soils, storm patterns, and local rules so you can keep water where it belongs. Let’s dive in.
Why De Smet basements get wet
De Smet’s wet season ramps up in spring. April through June are the rainiest months, with May and June seeing the most moisture from snowmelt and thunderstorms. You can see this spring spike in the De Smet climate normals on the NOAA summary for the area’s station data here.
Our landscape includes prairie potholes and nearby wetlands like Silver Lake. These hold water and can push groundwater higher in low spots during wet spells. When that overlaps with silt loam soils common in Kingsbury County, water can run and pond rather than soak in quickly. Local soil tables show many silt-loam map units in the county, which drain more slowly than sandy soils. You can view the county soil tables here.
Sump pumps: your first line of defense
When a sump pump makes sense
You likely need a sump pump if you see seepage through basement walls, have a history of water in your basement, or your footing drains already feed a sump pit. In wet springs, a higher seasonal water table and De Smet’s soil mix add to the need. See homeowner-friendly sump guidance here.
Choose, size, and place it right
Submersible pumps are common for basements. Many homes use 1/3 to 1/2 HP pumps, but you should size to your expected inflow and storm peaks. Use rigid discharge piping inside the house and a check valve to keep water from running back into the pit.
Discharge routing that will not bite you
Do not route clear-water sump discharge to the sanitary sewer. Many cities prohibit this because it can overload sewers and cause backups. See a typical municipal example of prohibited connections here. In De Smet, discharge to daylight, a storm outlet, or a roadside ditch may be allowed. Always verify with De Smet City Hall here before you change anything.
Aim to discharge at least 10 feet from your foundation and at a spot where water will not flow back toward your house. Use a check valve on the discharge line, and make sure the outlet cannot flood and drain back toward your home.
Power and redundancy
Heavy storms can mean power outages. A battery backup pump or a generator connection adds protection. Sump alarms and dual pump setups are also smart options, especially if you have a history of significant inflow.
Quick maintenance routine
- Test the pump and backup monthly in spring.
- Clean the intake screen and pit, and make sure the float moves freely.
- Check the discharge for clogs or freezing.
- Confirm the check valve closes properly.
Stop sewage from backing up
What a backwater valve does
A backwater valve installs on your building’s sanitary drain to stop sewage from flowing back into basement fixtures during a surcharged sewer event. South Dakota’s plumbing rules require approved backflow devices and allow local enforcement on where they are needed. You can read the state plumbing rule reference here.
Note: the check valve on your sump discharge only stops clear water from re-entering the pit. It does not protect your sanitary line. You need both protections if both risks apply.
When to consider one in De Smet
If any basement fixtures or floor drains sit below the elevation of the next upstream manhole, or you have had backups before, a backwater valve is a strong safeguard. Keep it accessible for inspection and cleaning. Local rules vary, so confirm with the city or your plumber before installing.
Grading and surface drainage that work
Target slopes around your home
Grade the soil to drop about 6 inches over the first 10 feet away from your foundation wherever space allows. This standard helps keep water moving away from your walls. See the building guidance on grading here.
Manage roof runoff
Keep gutters clear, and extend downspouts so water discharges at least 10 feet from the foundation or into an approved storm outlet. Avoid letting roof water soak next to the house.
Guide surface water
Use shallow swales to steer water to a road ditch or approved outlet point. Where groundwater or seepage is a driver, a perimeter drain tied to a sump may be needed. Protect window wells with covers and gravel, and give them a drain that ties into a safe outlet.
Plan for freeze risk
External lines can freeze in winter. Many South Dakota cities use a frost depth around 42 inches for construction, which matters if you bury discharge piping. See an example municipal code with this frost depth reference here. Check local depth and rules in De Smet before you trench.
Your De Smet spring prep checklist
- Inspect gutters and ensure downspouts discharge 10 feet from the foundation or to an approved storm connection.
- Confirm whether sump discharge to the sanitary sewer is prohibited. Call De Smet City Hall at (605) 854-3731 before you alter any connections.
- If you have basement fixtures or a floor drain below the upstream manhole elevation, ask a licensed plumber about a backwater valve and keep it accessible for maintenance.
- Test your sump pump and any battery backup before spring. Clean the pit, confirm the float and check valve work, and ensure the discharge is clear.
- Regrade low spots to achieve a steady slope away from the home. If lot space is tight, use swales or surface drains to route water safely.
- If seepage persists or groundwater is high, get a drainage assessment and consider perimeter drains or internal drain tile to a sump.
Permits and local help
Rules for sump discharge points and backwater valves can be city specific. Start with De Smet City Hall, 106 Calumet Ave, PO Box 70, De Smet, SD 57231, office (605) 854-3731, or visit the city website here. For flood risk context, you can check your property on FEMA’s Flood Map Service Center here. Your licensed plumber can also advise on code and device requirements.
Keeping water out of your basement is about stacking small wins: smart grading, clean gutters and extensions, correct sump pump setup, and a backwater valve where needed. If you are planning to sell this year, these fixes also help buyers feel confident about your home.
If you want local insight on how to prep your property for spring showings or a pre-listing consult, reach out to Molly Hopper. We are always glad to help you protect your investment and move forward with confidence.
FAQs
What causes spring basement leaks in De Smet homes?
- Spring brings more rain and snowmelt, local wetlands can push groundwater higher, and common silt loam soils shed water more slowly than sands, which increases surface runoff.
When do I need a sump pump in De Smet?
- If you see seepage, standing water, or have footing drains feeding a pit, a pump is recommended, especially during the April to June wet period.
Can I connect my sump pump to the sanitary sewer in De Smet?
- Generally no. Many municipalities prohibit it because it overloads sewers. Verify allowed discharge points with De Smet City Hall before changing connections.
How far should downspouts and sump discharge be from my foundation?
- Aim for at least 10 feet. Also keep the first 10 feet of soil sloped away from the house by about 6 inches to reduce ponding.
Do I need a backwater valve to prevent sewer backups?
- If basement fixtures or floor drains are below the upstream manhole elevation, or you have had backups, a backwater valve is a strong safeguard and often required by local rules.
How do I prevent a sump discharge line from freezing?
- Route to an outlet that drains freely, avoid shallow runs that pond, and where feasible bury lines below local frost depth or use insulated above-ground options that can drain after each cycle.
