Extremely high-pressure water literally blasts the built-up waste your RV’s holding tanks until they are “factory clean”

Kleen Tank. We get your tanks — holding tanks, in your RV — well, clean (or “kleen” as we always like to say!). It seems like a pretty easy concept to understand, but time and time again, RVers just don’t seem to understand what it is we actually do. So here we go.

The tanks in your RV
As you know, all RVs (okay, maybe not all RVs, like pop-ups and pickup truck bed models) have holding tanks. Most often, that’s a fresh water tank (which we don’t clean, but we do have an excellent article on why you should sanitize it frequently and how to do it), black tank (that’s the nasty stuff), and one (or more) gray tanks (that’s the “other” waste liquids).

Most RVs have one black and one gray tank, though the largest we did — an Open Range fifth wheel — had two black and three gray tanks (that was quite a job!).

Tank capacity ranges in size from 20 gallons to well over fifty (the biggest we cleaned was 87 gallons). Gray tanks tend to be a bit bigger than their corresponding black tanks, but some RVs have them all the same size.

How a holding tank is constructed
Your RV’s holding tanks work primarily through gravity. Think of them as big, squarish plastic boxes. The bottom of the tank is slanted toward one end. This makes solids and even water waste want to “fall out” (or down) to the lowest end of the tank.

At this low end, there is a hole with a pipe that exits your RV and where you eventually connect your sewer hose. Through this pipe (and the sewer) hose, waste leaves your holding tank when the gate valve holding the pipe close, is opened (by pulling the tank pull handle).

The holes for the drain pipes in your tanks is located on the front-facing wall of the tank, at the bottom. It is sometimes in the center of the tank or at one end, depending on the manufacturer and layout of your RV’s waste disposal system.

What about onboard tank spray systems?
Nearly every RV manufacturer has a spray system built into their black tank. This system uses water from your site’s water supply at RV park pressure and increases the overall water pressure into the tank by a reduction in the water pipe and spray head extending into the black tank. If your RV park’s water pressure is 50 PSI, your spray system in your black tank is likely somewhere around 100-150 PSI.

This spray system works to rinse off surfaces in your black holding tank. We recommend that you turn it on (connecting a separate water hose to the inlet valve near your dump valves) while emptying your black tank. The extra turbulence will help to keep waste and water moving out of your black tank as you empty it.

Your gray tank(s) do not have this flushing or rinsing feature.

What is happening in my tanks?
When you pull a holding tank’s pull handle, a gate valve opens and whatever is in the tank (being held back by the gate valve) is free (through gravity) to exit the tank and travel out through the sewer hose.

In an ideal situation (you use plenty of water, there’s no enzymes or chemicals to break down waste into a slurry, you use your black tank flush system to create turbulence in the tank), almost everything in your tank is eliminated when you dump them. But this is rarely the case.

If you use enzymes or chemicals in your tanks (especially your black tank), those additives are dissolving solid waste into a thick, pancake batter-like slurry. This is tough to get out of your tank. It sticks to tank surfaces.

Also, because of the way the exit hole is drilled into the front of your tanks, waste tends to gather around it, piling up at the low point, up against the front wall.

Finally, as RVers, we tend not to use enough water in our tanks when we use the restroom (especially). This makes the contents — solid and semisolid waste — in the black tank concentrated and can be difficult to empty completely.

Yes, your RV black tank has a flush system. But it’s more a sprayer or rinsing system and can’t generate enough volume nor pressure to keep your black tank completely clean.

Some RVers use a product like the Valterra Flush King backlash valve and that’s a great way to quickly introduce — and then evacuate — tank-fulls of water into your tanks. But if what’s in there is sticky or built up over time, there is only so much they can do.

So what does Kleen Tank do?
Simple. We go into each of your holding tanks with a high-pressure water pump and use water at 1500 PSI through a specially-designed cleaning nozzle to hydrogen your tanks clean.

The agitation process of 1500 PSI water completely knocks everything off tank walls, from corners, and breaks up any accumulation, mounds, or caked-on debris and sediment. We literally blast the inside of your tanks clean with high-pressure water.

Then, using that same backlash valve, we flood your holding tanks — first your black tank, then your gray tank(s) — and flush them out until they are completely clean. We like to say they are “factory clean.”

Should I have the process done?
Absolutely. You’ll be shocked and amazed (we were, the first time we had it done on our RV) at what comes out of a “clean” holding tank. And getting your tanks professionally cleaned is the first step in keeping them that way.

In fact, we spend about as much time teaching you about caring for your tanks as we do cleaning them. Make an appointment today or call or email us with your questions.