Of the countless responsibilities inherent in operating a foodservice establishment, one of the most often overlooked and least understood is the proper care and maintenance of a grease trap or “interceptor.”

With the possible exception of vent hood maintenance, no other part of a foodservice establish­ment’s basic infrastructure can cause greater potential for service interruption, regulatory sanction and squandered revenue if not properly understood and maintained.

As such, every proprietor or manager would be well advised to arm themselves with as much information as possible. Though potential questions are many, the following should go a long way toward protecting you and your business from potential pitfalls.

To best explain what a manager should know and look out for, the following five questions and subsequent answers will arm any manager or proprietor with the information necessary to understand the difference between fact and fiction.


Likely no single statement is heard more often from restaurant managers regarding their grease trap. In some cases, this is born from a lack of understanding how a grease trap works. In other cases, unscrupulous operators or incompetent service providers have given bad information that misleads the facility manager. More often than not, the person giving such advice to a site manager either does not understand the problem or understands the problem completely but is banking on the customer not knowing any better. In the case of the latter; that individual is simply trying to get the manager to unnecessarily pay for additional work.

The fact is, once completely evacuated and steam-cleaned, the trap will immediately begin re-filling. Once the water level reaches the outlet line on the city side of the trap, it will maintain that level going forward. Generally, a 1,000-gallon trap at a busy restaurant seating 100+ customers, will return to its normal level in a matter of hours since water continually runs in the kitchen through­out the day. Remember, the contents of the trap should determine the need for cleaning, not the level. Generally speaking, when “FOG” (fats, oils and grease), organic material and trash comprise 25% of the trap’s capacity, it’s generally time to clean the trap.


When a plumber gives you this piece of advice, find a new plumber. Better yet, call your grease trap service provider. There is a saying, “Plumbers prefer to repair; grease trap companies expect to clean.”

The fact is, a recently cleaned trap can overflow just as easily as one in need of cleaning. When a trap is overflowing, this clearly indicates a blockage exists in the sewer line between the trap and the city sewer tap. When drains are overflowing in the kitchen, but the trap appears to be at its normal level, this indicates a stoppage in the sewer line between the kitchen and the trap. In either case, a competent technician should only recommend cleaning the trap as a last resort.

The appropriate course of action is a hydro-jet cleaning of the sewer line to completely remove the blockage. Using other equipment such as sewer “snakes” will only provide temporary relief as they are designed to penetrate the blockage – not to clean the line. Line jetting is a feature that any well-rounded grease trap service provider should offer. Generally, a trap service provider should possess this expertise and, more often than not, they should be able to provide this service at a rate much cheaper than a conventional plumbing company. If a grease trap service provider does not, at a minimum, have jetting equipment on their vacuum trucks, it is very difficult to properly clean a trap. Some companies even offer dedicated “jet trucks” that offer both preventative and emergency line services.

Facility owners and managers would do well to know what services are offered by their current or prospective service provider. A fully integrated service provider can offer meaningful savings in time and money; creating a “one-stop shop” for multiple service needs.


It is important to understand that, while regular and proper trap cleaning and maintenance is essential to optimum plumbing performance, it is only half of the battle. Regular drain line hydro-jet cleaning should be an essential part of any total plumbing maintenance plan. This component of a restaurant’s total maintenance plan will do more to save time and money in plumbing bills, lost productivity, etc.

With the, combination of a high volume of hot water, coupled with detergents used to disinfect and clean a commercial kitchen, much of the FOG produced in a commercial kitchen enters the trap in solution. Ideally, the trap slows water flow and allows the material to cool. However, a portion of· the material still travels, in solution, to the sanitary sewer. As the water moves downstream and cools, it will adhere to the inside of any plumbing system, (e.g. sewer lines).

The same holds true for the drain lines going from the kitchen to the trap. At closing time and as the water flow stops, material remaining in the sewer lines will settle, collect and harden over time, creating another opportunity for stoppages.

Another culprit responsible for a great deal of drain problems is the commercial garbage disposer. Though plumbing code varies state-to-state, most states mandate that a disposal line go directly to the sanitary sewer, thus bypassing the trap. Also included in this line could be restrooms, hand-sinks and condensation drains for ice machines and coolers. Therefore, FOG and ground food debris have the opportunity to mix with material coming from restrooms and are often hit with icy-cold water – not a pretty picture. Imagine, if you will, frying a pound of bacon at home. If you allow it to cool in the skillet, it will thicken over time. Now, imagine what happens when ice water is poured over it. That is an accurate depiction of what typically occurs in a sanitary sewer line.

Many vacuum service companies advertise hydro-jet services. Typically, this would indicate their ability to clean the main service line going from the kitchen to the trap and from the trap to the sanitary sewer tap. As one can see, a thorough cleaning of the sewer system should also include jetting through the individual kitchen drains themselves. A sewer drain system is like the human body; the sanitary sewer (main line) is the artery. However, a commercial kitchen has many “veins” (individual drain lines) that feed into me main “artery” as it travels to the trap and sanitary sewer. Often times, a nuisance stoppage can be isolated to a single drain line rather than me entire system.

Regarding the above, it is important to ensure that employees are using best kitchen practices to mitigate FOG, organics and trash from entering the trap or sanitary sewer lines:

  • Disposers are removed or disabled.
  • A hydro-jet line cleaning is performed on a regular basis using equipment capable of producing a minimum water stream of 2500 psi (pounds per square inch). Further, it is important to ensure that the entire system is cleaned, at least twice annually.


In most states, it is a requirement that both foodservice establishments and grease trap service providers maintain copies of manifests for periods ranging from 3 to 5 years. Failure to produce past copies of manifests during health inspections can mean significant municipal fines and can often result in the facility being forced to unnecessarily clean their trap, whether needed or not. Things happen; manifests get misplaced. A facility manager should always feel they can look to their service providers for additional manifest copies in a pinch.

When examining service providers, record keeping options can and should also play a role in who can best meet the food service operator’s needs. There are a handful of companies offering online access to manifests and other important records. Typically, each customer or site will have a distinctive access code or password that will enable them to go directly to their records and print duplicate copies without ever having to pick up a phone. This time saving feature provides added peace of mind and, as they say, time is money.


In today’s economic times, that phrase is heard more often than ever. However, as the following will explain, cheapest isn’t always best.

It is important to know who you are dealing with. If your “service provider” is five states away, possessing nothing more than a card table and a telephone and is sub-contracting the work, do you really know who you’re working with? Who is the responsible party? With heightened regulation, many foodservice operators do not understand that chain-of-custody remains with them until final disposition at a permitted facility can be shown. If a low budget operator dumps their material in a bar ditch or down a deserted road, the generator is the responsible party. Authorities will certainly go after the transporter but, at the end of the day, everyone will be sanctioned, including the foodservice operator. Make sure your service provider can provide references and that they have “skin in the game.” The person doing the work and the site operator are the responsible parties, not the person sub-contracting the work.

One of the oldest tricks in the grease trap business is often referred to as “phantom gallons.” Essentially, a low per-gallon rate is provided but the size of the trap is overstated. If a facility is quoted $0.15 per gallon for a 1,500-gallon trap but, in actuality, the trap is 1,000 gallons, the effective rate becomes $0.225 per gallon.

Sometimes this can be the result of malice, or in other cases it can be pure laziness on the part of the service provider, taking the previous company’s “word for it” off the old manifest. In any event, site managers need to know their trap size and require their service provider to “certify” the actual size. If necessary, get a third-party certification. One should never take the size off of plumbing plans. A trap may have a maximum capacity of 3,000 gallons but it may be plumbed to only have a carrying capacity of 2,500 gallons.


Grease traps, although generally out of sight, can be one of the greatest sources of service interruption and revenue loss. Knowing what you have, what your risks are, how you should maintain it, and with whom you are working – will go a long way in helping to mitigate downside risk.

Further, be careful in pursuing the lowest price. Oftentimes, this does not equate to either best value or service. A well designed plan for trap and line maintenance – if properly executed – will provide meaningful savings in avoiding unnecessary plumbing fees, downtime and potential fines, which will far outweigh a penny or two per gallon savings in the long run.

Darrell E. Rogers is chief executive officer of American Allwaste Corp.