RV plumbing

Happy New Year everyone! I hope 2015 is a healthy and prosperous year for all of you. Personally, 2014 was not without its challenges, so I am not sorry to see it go. Hopefully 2015 will be better.

Over the Thanksgiving holiday, I took a family vacation and went trailer camping in the California High Desert with other families. All told, we were a total of 14 RVs and trailers. It was quite a remarkable little community. Every family was equipped with their "desert toys," meaning dirt bikes, quads, Polaris RZRs, and the like. It was great seeing kids and seniors alike enjoying themselves on these adrenaline toys, and having communal dinners around the campfire afterward.

Since this event was in the middle of the desert, there were no campsite hook-ups for water and power. This was what they call "dry camping." The only water available was what you brought with you, and the only electrical power was from whatever generator you had.

The trailers, RVs, and fifth wheels (which are trailers on steroids) were all equipped with water storage tanks. Needless to say, the bigger and fancier the trailer, the larger the water tank. Our rented trailer was a modest 20-foot unit, and I would estimate the water tank was about 40 gallons. I had been told it was larger, but when I ran out of water I quickly realized it was not as large as I had been told. Imagine a family of four living on 40 gallons of water for four days, including showering (only when absolutely necessary), washing dishes, and of course, flushing the toilet. That's just 2.5 gallons of water per person, per day. Water conservation was obviously a priority.

These trailers are also equipped with two waste holding tanks, one for gray water and one for black water. There is a handy control panel that tells you how full the three tanks are (in one-third increments). The trouble with this panel was the sensors were not very accurate, nor was their scale very linear. It took nearly three days to reach the “two-thirds full” indicator light on the water tank, but then it dropped rapidly down to one-third, and shortly after that the delivery pump was sucking air.

Having run out of water with another day to go, my wife drove 25 miles into town to pick up 10 gallons of water. When I added this to the tank it again read two-thirds full, but at this point I was seasoned enough to know it was trying to trick me. However, I also knew that we would get by comfortably on that amount of water for one more day.

The water closets in these trailers are similar to those on boats and are extremely water efficient. They have no trap – they dump directly into the black water tank, so they require much less water to flush. The fixture seal is created mechanically by a semi-spherical ball joint that rotates to flush the fixture and rotates back to seal the fixture. However, I noticed that the seal is imperfect, at least in the unit I rented. When you drive around with the trailer, the sloshing of the black water causes some of the associated odors to escape the seal and fill the trailer. When the trailer is motionless this doesn’t seem to happen.

Other appliances on the trailer were equally fascinating, as they are much different than the familiar norm. The refrigerator can run from either propane, when generator power is not available or electricity when it is available. You can select which energy source you want to use, based on your relative supplies of gas for the generator versus propane. The water heater was the same – you can select the energy source as either propane or electricity from the generator. The furnace, which was crucial at night since temperatures dropped from the 70's by day down to the 30's at night, required both propane and electricity to function – propane for the heat and electricity for the fans. On night two, we woke up to a very cold trailer. I thought the propane had run out, but it turns out our battery had run low because the generator was not on at night and I had left the water heater set for electric power accidentally. Oops.

In short, the energy supply for the trailer was a constant balancing act between the propane and gasoline fuel sources. Appliances had to be carefully selected and operated based on the availability of the two fuels, not wanting to run out of one or the other.

Lastly, the gray and black water tanks required continuous scrutiny. These tanks are each smaller than the water supply tank. I was not told how large they were, but it was clear from how quickly they filled up that they were not as large as the water storage tank. Obviously, the first priority with these tanks is that they not fill up completely and cause an overflow from the fixtures. The second priority is that you not leave the campsite with these tanks full if you can avoid it because you waste gasoline hauling the waste water around in your trailer.

When camping, you produce a great deal more gray water from the sink, shower and lav than you do black water with its highly efficient water closet. On my trip, I discovered that as the water tank dropped to two-thirds full, the gray water tank had reached two-thirds full. This concerned me, so I asked a highly experienced camping friend if I could dump the gray water on site. He explained that if you dig a hole, you can drain the gray water, allow it to percolate into the earth, and then backfill it. This was good news since the tank was nearly full. Digging said hole was no easy task, as the sandy earth was hard as concrete and required a pick-axe to break through the 6-inch thick, crusty top layer. Below that, the digging got easier as softer sand was exposed.

When I drained the gray water tank, I estimated that it contained about 15 gallons of waste, so the tank itself was probably 20 gallons. The black water tank could not be drained on site, so I never had means to gage its size, but fortunately it never reached capacity. The level sensors in the black water tank were not functional, which is not uncommon since they are easily fouled by debris in the tank, so I had no means to determine how full it was. But, it never reached capacity – thankfully.

Anyway, some of you reading this might be experienced dry campers and might be chuckling at my ignorance. This was my first dry camping experience, so your chuckles are warranted. If you have never been dry camping before, I highly recommend it as a means to travel deep into nature and live comfortably in a remote and beautiful environment. And, you might learn a little about plumbing from an entirely new perspective.

Timothy Allinson is vice president of Engineering at Murray Co., Mechanical Contractors, in Long Beach, Calif. He holds a BSME from Tufts University and an MBA from New York University. He is a professional engineer licensed in both mechanical and fire protection engineering in various states, and is a LEED accredited professional. Allinson is a past-president of ASPE, both the New York and Orange County chapters. He can be reached at lagunatictim@gmail.com.

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