While a flooded basement is definitely a problem, a sewage backup is an emergency. Sewage backups are caused when storm water overwhelms the sewer lines, which then can back up through basement drains and fixtures.
If you think the water in your basement contains sewage (the smell is a dead giveaway) call a water mitigation professional immediately to clean it up. Raw sewage is full of bacteria, viruses and microorganisms that can cause all types of health problems, including skin rashes, gastrointestinal issues, and even dysentery. It's important that any sewage be cleaned up properly and immediately to avoid these risks to you and your family.
Even if the water is just rain, you must get it dried up as quickly as possible.
- If the water is draining slowly, use buckets or a portable pump to get it out faster.
- Go after remaining puddles with a wet/dry vac.
- Open any doors and windows to increase ventilation, and run fans to circulate fresh air.