A sump pit in a St. Charles basement collects water that moves in from the soil around the foundation. Many homes here also sit over ground where shallow groundwater and surface water move together after heavy rain. Water in the pit is not meant for drinking, but a sample from it can still show what is entering the house and whether the drainage around the home is working.
Know what the pit is collecting
Pit water is a mix. It can include rain that soaks in near the home, seepage from the ground along the foundation, and water from the surrounding soil that rises when the water table is high. Depending on the lot, it may also pick up dust, soil particles, and residue from the concrete and metal parts in the pit. A sample describes that mix at one moment, so write down the weather when you collect it.
Before you collect a sample
Avoid sampling right after a storm, since that can capture only the highest water level and not the usual condition. If you want to compare, plan a second sample after a dry spell. Wear gloves and use a clean container that a testing lab supplies or that is labeled for water testing. Do not use a jar that held cleaning products, food, or anything with a strong smell.
How to collect the sample
- Sample water that is already in the pit, and keep the pump working so the pit does not overflow. Do not test a pit that is backing up into the floor.
- Remove the lid and check for a floating layer of debris, which you should leave out of the sample.
- Dip the container below the surface, away from the pit walls, and fill it without splashing.
- Cap it tightly, label it with the date, time, and weather, and take it to a lab the same day if you can.
What to test for
- Total hardness, which shows how much mineral content is in the water draining toward the home.
- Iron and manganese, which can leave orange, red, or black stains on the floor, the pump, and anything the pit water touches.
- pH, which shows whether the water leans acidic or basic.
- Coliform bacteria, which can indicate that surface water is reaching the pit. A positive result does not tell you where the bacteria came from.
- Nitrate, if fertilizer runoff from nearby lawns or fields is a concern.
- Radium and uranium, which occur naturally in some parts of the region. A lab can test for them if you want to know what is in the groundwater near your home.
Reading the results with care
A pit result is not a drinking water result. Lab reports list values with units and reference levels, and it helps to compare the pit results with your tap water report. High hardness in the pit does not prove what is in your drinking water, though it can explain scale or residue in the basement. If stains appear, the test can help match the mineral causing them, which tells you what to clean and what to change in the drainage.
Next steps in St. Charles
If the pit fills quickly after rain, check the gutters, downspouts, and grading around the foundation before making any other changes. Water that sits near the wall for long periods can add dampness and staining to a basement. If results show bacteria or high levels of a metal, talk with a licensed plumber about the source before deciding on repairs, and keep the lab report with your home records. A sample taken at the right time gives you a clearer picture than guessing, especially in St. Charles, where rainfall and the water table both change through the year.