Professional Carwashing & Detailing

Preventing pit problems

October 11, 2010

Bay pit care is an often overlooked task, and most people think that the water just runs off and ends up in some black hole. But while bay pit care may not be a top priority for most owners, it could cost them money and could even cost them customers if it’s ignored.

Ominous odor effects
The effects of bay pit odor can devastate a wash’s business. Bay pit odor will generally come from either biologic or chemical causes.

Simply speaking, bacteria creates foul odor in a carwash. Chemical odor develops for two reasons — the first possibility is from one type of chemical; the second can be from a chemical reaction.

However, there are preventive ways to help eliminate bay pit problems. One of the easiest ways to help a self-serve wash is to prevent dumping at the site.

Things like:

  • Oil;
  • Grease;
  • Human or animal waste;
  • Antifreeze; and
  • Trash are just a few of the common problem causers.

The best thing to do is to put up signs to discourage people from dumping at the carwash. If these signs are placed near the coin box, it will give customers a better chance of reading them.

Also, remind customers that dumping is illegal and they can be prosecuted for doing so. Remember whatever they leave, the wash sends out to the sewer; this leaves the carwash owner/operator responsible for what goes out their drain.

Things like oil, grease, antifreeze and other contaminants will result in a large fine from the Environmental Protection Agency (EPA) or Department of Conservation.

Another suggestion is the installation and use of a camera system. This will discourage dumping and theft.

Regular cleaning
Regular pit cleaning will also help reduce odor in the self-serve bays. Cleaning the bay pit at least twice a year is a good suggestion. Pump it once before summer and then pump again before fall.

When summer rolls around bacteria is most likely to become a problem in the bay pits. By pumping them out, the operator removes some of the source of food for bacteria to live and multiply from.

While the pit is cleaned out, check for cracks or leaks in the bay pit floor or walls.

Also, the drain pipes that leave the self-serve bay need to be cleaned. Flush them with high pressure water. Many times the pipes will have low spots that can hold much debris and bacteria in them.

Always clean the side walls with bleach or chlorine. Sealing the bay pits (if made of concrete or brick) will help reduce bacteria from living in the walls of the concrete.

Treating odor
If an owner is having trouble with a chemical odor, changing the chemicals in the equipment room or stopping illegal dumping will help immensely.

Bacteria problems can be a little tougher. Control and elimination of bacteria related odors depends on many factors. It’s important to remember that the treatments can vary as much as the problem.

The easiest way to control smell is through the use of chemical treatments like:

  • Chlorine;
  • Peroxide; and
  • Bleach.

All can be effective at removing odors caused by bacteria. The benefits are that they are relatively cheap, easy to get a hold of, and there’s no mechanical items to use.

The downside is that if you have a reclaim system, these chemicals can cause pump damage. They could also have reactions with chemicals being used in the carwash and on the car.

As with any chemical, start with a small amount and add only enough to solve the problem. Any chemical that goes beyond the discharge limits (sewer limits) can incite issues with the EPA.

If the problem is more consistent, use a floating chorine puck. They can be found at most local pool supply stores.

Ozone and bugs
Ozone can be used to control bay pit odor. It is a very effective way to kill bacteria. Ozone also helps break down many other items in the water including chemicals, which can benefit reclaim users.

The disadvantages of ozone are the regulations on how much ozone can be discharged into the environment.

The owner can bubble air into the pits to help displace oxygen in the bay. This will help keep some forms of bacteria from growing.

Bugs in the bay pits, bacteria and enzymes can also be used to control bay pit odor. Some strains of bacteria actually can grow faster and crowd out the bad bacteria.

Enzyme applications can eliminate the byproducts of the bacteria (where the odor comes from) and destroy them.

The disadvantage to bug usage is the cost. It can become expensive, but is easy to use: either by injection or by manual labor.

They also have other attributes that may be helpful in reclaim situations like lowering:

  • BOD Levels:
  • Oil and grease; and
  • Suspended solids, to name a few.

As with any other chemical, it is important to know what the discharge limits are for the area.

Design it right
When designing a new carwash there are some things an owner can do to help protect themselves from bay pit odors. The first is to make the whole system a loop. This means bay one will flow to bay two and then to bay three and so on. This will allow the owner to but a pipe from the last bay pit to the first bay pit.

Use these pipes to pump water back to the equipment room and then use many of the options mentioned before to control the odor to make odor control automatic, saving the owner time and the headache of mixing chemicals every day.

A flat bay pit lid with risers is another item of maintenance which can be used. This bay pit lid will capture sediment on top of the plate and can be cleaned off daily.

This will stop some debris and dirt from entering the system, and also allow the owner to know when someone has dumped illegal items at their carwash.

An offense on odor
Odor can drive away some customers or entice others to come back.

Take the time and make the effort to stock up on chemicals and know about the methods to control bacteria odor in the system.

Ask customers about the odors they smell to find out if they are offensive or noticeable.

Always treat the system with the recommended dosages when possible and use common sense when applying chemicals to a system.


Nick Miller has worked in the carwash industry for 15 years with Water Perfect LC. and other companies. Nick can be reached at nmiller@waterperfect.com.