Drain plumbing design and maintenance

Have you spent large amounts of money on electrical motors? Are your inverter drives failing? Are your customers always complaining that the load came out wet? Does a bad smell come from your washer tubs? You might have a draining problem. We have come across so many installations where the drain design has been overlooked and the machines won’t drain properly. The other factor to consider is ongoing maintenance required to keep your drains clean.


PVC line or to a direct pit? Both designs have their pros and cons. The most important thing to remember is that drain plumbing should have as fewer elbows as possible. Commercial machines dump the water using gravity, this means the machine should be elevated higher than the drain plumbing to allow easy water evacuation.  For enclosed PVC plumbing, drain traps should be avoided per individual machines unless required by code. The truth is that individual traps for each machine will require constant cleaning. If this is required by code in your jurisdiction, your architect design should allow enough space behind your machines to go back and forth as these traps will require maintenance often. Instead, I would prefer a trap in the main line going to the bulkhead with cleanouts exposed outside the bulkhead to facilitate cleaning without jumping inside the bulkheads. Your plumber should always give a proper slope to the correct side of the drainage. I have seen slopes to the wrong side of the drain.

Pit or drain troughs are also commonly used and required by most cities plumbing codes. These come in a variety of forms. They could be built-in in your concrete base or PVC prefabricated troughs, which you can install behind your washers.  Same as the enclosed PVC pipes, drain troughs don’t come maintenance free. PVC trough’s lint interceptors must be cleaned on a daily basis. If you have them built on your concrete base, then some type of strainer must be used to avoid coins, credit cards and a variety of junk to form a blockage under concrete drain lines. Letting this accumulate over time turns it into rock-solid junk that is extremely difficult to remove and leads to costly emergency pressure flushing calls. On the other hand, concrete troughs tend to create mold and washers frames corrode prematurely due to constant oversudsing often reaching the motors and motor’s harnesses.

My favorite design is a combination of both. Enclosed PVC lines behind the machines connected to a main pit somewhere in the back of your store, or depending on your climate, outside of your store. In this configuration, each bulkhead’s main line drain has its own trap, and each line is connected to a single pit, with its proper lint interceptor. The interceptor is often times made of perforated PVC stainless steel seating right on top of the sewer line. I prefer this configuration because it facilitates working behind the machines, prevents excessive corrosion in rear panels, prevents motors and their harnesses going bad due to constant contact with corrosive detergents and suds, and prevents bad odors from coming from your drains.

We have seemed many configurations and there is no right or wrong when it comes to choosing your next store design. However, the drains should be given some extra thought as it can make the difference between machines failing frequently, clogged drain pipes and dissatisfied customers.


Independently of your configuration, drains require cleaning maintenance, for some busy locations it may be every three months for others it could be every six months or a year. Coins do accumulate inside the drain valve, at least once a year take the drain valves out and remove the coins.

Don’t wait for a machine to break down before you look for good quality maintenance service. Any downtime could cut into your profits and irreversibly affect how your brand is perceived by your customers. To protect your investment, we offer preventive maintenance contracts. For a free quote please call 1-888-618-0526.

Leave A Comment