Basement Floor Drain – Keeping Your Home Dry

The basement floor drain provides an exit for water in the basement before it reaches the windows. For years, basement floor drains have been a requirement of most international and local building codes. 

basement drain

Floor drains are a safety feature to prevent basement flooding. Home builders install them during construction before pouring concrete floors. Although expensive, you can add them to houses built without a drain. Regular maintenance will keep your floor drain operating properly–when needed and prevent it from smelling of sewer gas.

Here’s what you need to know about floor drains and floor drain maintenance.

Standard Basement Floor Drains: What They Are

Basement floor drains are usually hooked up to the sewer system or a sump pump system. They look like your sink drains–with piping and a P-trap. The P-trap prevents sewer gas from coming back into the house. Floor drains contain larger pipes buried under the basement’s concrete floor.

Quite often, floor drains are in laundry rooms, furnace rooms, or utility rooms—concrete floors slope towards the drain hole in some cases. Even if the floor is perfectly level, water gets to the hole and drains before getting too high on the walls.

Note: According to the International Plumbing Code (Section 714), Backwater Valves–also known as sewer backup valves–are now required to prevent sewage from entering basements. They are installed in the drain line before it exits the house footprint.

Floor Drain Maintenance: How to Clean Your Basement Floor Drain

A clean floor drain removes water in your basement, prevents sewer gas odor, and helps keep sewage backup out of your home. Make sure you spend a few minutes every six months keeping the drain in top operating condition.

  • Cover. Remove the cover and clean out any visible debris.
  • Clean. Pour at least a gallon of hot water into the drain. (Boiling water is better.) Wait about 15 minutes.
  • Refill. The water will also refill the P-trap to block sewer gas.
  • Rinse. Rinse by pouring ½ cup to 1 cup of baking soda down the drain. Follow this with a cup of vinegar mixed with a couple of quarts of hot water. Wait about 10 minutes and flush the drain with another gallon of hot water. There is no exact formula for the mixtures. As long as it foams, it is working. You can also use a commercial product like Roebic Main Line Cleaner.
  • Replace. Make sure you get the cover back on. If it is missing, you should get a new one. (Saves fishing out Lego.)

Lazy-Man Hint: My hot water tank is 4’ from the floor drain. I drain the tank into the floor drain–with a hose. The hot water going down the drain serves a useful purpose.

A New Floor Drain in an Old House

If your house doesn’t have a floor drain but has water problems, you can install a new drain. You might be able to hook up to the existing drainage system. But in most cases, it is easier and less expensive to collect water in a pit, then pump it out to flow away overland.

Whichever of the following options you might choose, be prepared to spend $5000.00 to $15,000.00 – more in bigger houses or homes with complicated applications. You will need to hammer out a lot of concrete, then replace it or patch it and remove and replace the soil while maintaining the proper slope.

Installing a floor drain into an existing basement floor can be a daunting DIY project. Hiring a professional contractor is a good way to get the job done properly, on time, and with a warranty. Not to mention saving yourself some back-breaking labor.

Channel or Trench Drain

Channel or trench drains go around the floor’s perimeter or down the center. They move water to a collection pit. Then, a submersible or pedestal-style sump pump pumps it out of the house. Trench drains are common in car washes and repair shops.

Trench drains usually require the most concrete and soil removal. A slope of only ¼” per foot means you will be digging out an extra 5” of dirt at the end of a 20’ run of pipe.

Standard Basement Floor Drain

Installing a standard floor drain is less expensive than other options because it involves less concrete removal. First, pick the lowest point of the basement floor for the drain. Then, dig it out, trench a line to your pit, and pump the water outside.

If you do not have a sump pit and pump, you must dig one out. The International Plumbing Code Section 712.3.2 requires a minimum pit size of 18” in diameter by 24” deep. This YouTube video will give you a good idea of what you are getting into if you decide to take on this project yourself.

Sump Pit and Sump Pump

Basement sump pum installation diagram
Typical sump pump installation with interior perimeter drain. ( Image source.)

Sump pits and pumps are often used with other drainage systems to collect and remove water. They can also stand alone to collect moisture in high water table areas and pump it out. Water seeps into the pit from under the floor pad.

Sump pumps are a typical requirement in areas prone to flooding. They reduce the chances of water leaking into the basement from under the floor through cracks or where the floor joins the footing. Where I live, all new houses need sump pumps.

Exterior Perimeter Drain

In areas without high groundwater, an exterior perimeter drain or French drain may be a better option. It will keep the water from seeping into your basement and redirect it away from the house. In an area of high groundwater, the exterior perimeter drain will only be one part of a complete basement waterproofing plan.