Wednesday, August 27, 2008

The Secret to Trouble-free RV Holding Tanks

Holding tanks, certainly not the glitz and glamour of hitting the open road, are a fact of life when RVing. Most RVs have a black tank, one or two gray tanks and a freshwater tank. There’s no getting around it – without holding tanks we wouldn’t be able to enjoy the “home-style” plumbing features in our rigs. But holding tanks present mystery and perhaps even a bit of confusion to a new RVer. What, when, how…read on for answers.

An RV’s freshwater tank holds water a camper may use when no outside water hook-up is available – whether in a campground, at a rest stop or during travel. The water is pumped to your plumbing system via a 12-volt water pump – usually operated by a switch in the kitchen or bathroom. The most common freshwater tank maintenance task is sanitization. Remember, this is simply a tank full of water – infrequent use can cause bacteria buildup resulting in bad tasting or smelling water or even a bug that may make you ill.

Eliminate this unpleasantness by sanitizing with a bleach water solution. Drain your tank, fill half way with fresh water, add ¼ cup of bleach for every 15 gallons your tank holds, fill tank, run “cold” water through your faucets, run the “hot” water to get the bleach water solution in your hot water tank. Let stand for four to six hours. Drain the tank (including hot water tank via faucets) completely. Mix a ½ cup of baking soda with a gallon of water, pour into tank and refill tank. Open all faucets to allow the fresh water to pump throughout the system – this step removes the bleach odor. Drain tank once again and refill – ready to use. Even sanitized, it is a good idea to use bottled water for drinking and cooking.

One more fresh water tank tip – water weighs eight pounds per gallon – factor that weight in when traveling. I typically travel with only five or six gallons for rest stop needs. Most camps that do not have water hook-ups at the sites do have a water station to fill up prior to parking.

The gray water system is the holding area for waste water from showers, the bathroom and kitchen sinks, etc. Be careful when washing dishes not to let many solids – like rice grains, etc. – down the drain. It’s okay to leave the tank valves open when connected to a sewer system. Occasional odors can be treated with the same holding tank solution used for your black tank – nothing fancy required.

Black water is the boogieman of an RV’s holding tank system. This is where the “solids” reside. Plainly said, this is your toilet waste. Tip number one – DO NOT leave your tank open – even when you are connected to the campground’s sewer system. Your black water tank should be ½ to ¾ full before dumping. This little technique allows the suction of the sewer dump to force the solids out. That’s a good thing, no one wants stinky left behinds (no pun intended) to solidify on the bottom of your tank. Once that happens it is almost impossible to loosen it up and flush it out completely. It’s never a bad idea to run a few cycles of fresh water through the system when flushing the tank with a wand or other nifty tool meant for the job.

Black tanks need a chemical “holding tank treatment” and a few gallons of water added after dumping. Look for an environmentally safe, formaldehyde-free solution. These treatments come in liquid form (which I like the best), tablets (never sure if they dissolve) or granules. These treatments may also contain a tank conditioner to lubricate the valves and seals.

You don’t have to purchase camping store TP, either. Look for a one-ply product like Scott’s and your black tank will be fine. To test a TP put a sheet or two in a tall glass of water, allow to sit five minutes and stir. RV acceptable TP will disintegrate upon stirring. Lastly, nothing exotic should go down the toilet – waste and TP only, please.

A few more thoughts on holding tanks that you may find useful:

➢ The tank meters inside your rig rarely work. Use another system to determine when to dump your tanks.
➢ Use a sturdy sewer hose with several end connectors on board and carry a rubber donut – required at more and more campgrounds.
➢ You may run into a law that prohibits the sewer hose from touching the ground. Be prepared by carrying a few pre-cut gutters and a wood block or two.
➢ And lastly, you know the old saying…it doesn’t run uphill…much to the surprise of many campground engineers (especially in government parks).

So, there’s the fact of camping life that can’t be ignored. Just do it…


Anonymous said...

1 suggestion on the black water tank maintenance.When emptying both tanks,do the black water first. Then drain the grey water. the grey water will flush any solids still in the black water hose.

David McKnight said...

That's a great suggestion, anon. When you've been doing this a long time, you sometimes forget to mention the basics. Having been an RVer for many years, I know that's standard practice for most RVing vets.

We can't forget, though, that we get a lot of first-time buyers reading these. So, it's always great to have folks like you add the pointers we might have left out.

Keep reading, and keep replying.



Anonymous said...

One other thing I usually do is fill the toilet bowl clear full of water before I go to dump and after draining black water I dump the whole bowl full of water before shutting valve. I think this helps to flush the black tank. After I get the tanks empty I usually run a bowl full in the black tank just to keep everything wet.

Anonymous said...

If you know that your initial stop has a dump I suggest that you add a little TIDE and water to the black tank and let the movement of the rig wash the black tank. When you get to your stop dump the "wash water" from the black tank and rinse with water and you have a clean or at least cleaner tank.

Anonymous said...

After many years of emptying holding tanks I have found that dumping 5 gallon pails of water down the toilet, after the contents have stopped moving, helps to creat the flow needed to empty the tank. This seams to work better than using the wand on a hose. 2-3 pails and your good to go. I always put one pail in for travel, the movment helps to clean the tank. Cheers....

Anonymous said...

After dumping the black water tank, put a bag of ice down the toilet (or the ice you have left in your freezer), as this will knock anything loose from the sides of the tank while traveling home, and the melted ice will leave water in the bottom of your tank. We put the chemical in with the ice as well.

Angela said...

i am such a newbie at this, we have not bought our black tank yet. We are gutting and restoring a vintage 66 airstream overlander. we are a little confused {about a lot of things} {lol} --- however is there a general rule of about how many flushes you can get per gallon. i know it depends on who is using the bathroom and what they are doing. Just curious, do not want to be in the middle of a trip and can't use the bathroom. thanks for any helpful info.. Angela and Spartacus

Anonymous said...

Don't know if there is a specific rule of thumb on flushes per gallon, but there are some tips on water conservation, which do increase your flushes per gallon. For instance, don't fill the bowl with water. Instead, start by putting a couple of sheets of biodegradable TP in the bottom of the bowl before using. That helps the bowl contents go right into the tank, and you'll use a lot less water when you do flush.

Also, the tank that tends to fill up first is NOT the black tank; it's the gray tank. Water running down the galley sink (or even brief showers where you leave the water running, instead of shutting it off while you soap down). That fills the gray tank FAST.

AND, to keep the tanks flushing nicely when you're staying at a campground with full hookups, go ahead and connect to the sewer line, but don't leave the tank valves open. Check the tank capacity, and then drain the tank as it starts getting full. Gravity and the weight of the water (at about 8.35 pounds per gallon) will help flush the tank cleanly down the sewer drain, keeping it a lot cleaner. Good luck and have FUN!