The tip below was inspired by a discussion on the RV Basics Yahoo group. A member of the group wrote that he was advised to keep his RV black tank valve open during the winter to avoid freezing. The result of following that ‘tip’ was a clogged black tank.
I have to say that while I invaribly believe what I write… I don’t offer tips I wouldn’t follow myself. Several members of the group have passionately disagreed with me. I offer my opinions as food for thought. It’s up to you to decide what will work for you. Please feel free to add your comments below.
While I believe the mechanical methods: broomstick or awning wand down the toilet, toilet flush wands, back flushing, etc. for clearing a clogged black tank are usually the most efficient and cheapest, I see no problem with using chemicals if one wants to do so.
I’ve never agreed with those who caution against using Drano, Liquid Plumber, etc. in RV plumbing because it will harm something in the system.
RVs are plumbed using mostly the same plastic piping and fittings that houses are plumbed with. Even the ‘special RV’ plumbing fittings and parts are made from the same plastics. So if household plumbing chemicals are safe to use in household plumbing I cannot see why they are not safe for RV plumbing.
The only ‘seals’ in my RV’s plumbing are in the dump valves and they appear to be rubber. I have not found any evidence that plumbing chemicals have a harmful affect on rubber. Even if there is, I can’t believe that short term exposure during the unclogging of a black tank would be a problem. Rubber is pretty tough stuff and will be rinsed well with water after the project is complete.
As for these chemicals killing off waste digesting micro organisms, the Drano company website says their products are not harmful to septic systems. Okay, so it was the company saying that. I have to believe the FTC or an enterprising lawyer would have taken action already if it could be proven otherwise.
Keep in mind we are discussing how to clear a clogged black tank. We’re not talking about using these sludge busting chemicals on a regular basis. Once the tank is cleared, rinsed and ready for service again you can introduce new enzymes and bacteria back into the tank if you want to.
Then again, I don’t consider my black tank to be a mini septic system. It is simply a holding tank to store the waste until it can be properly disposed of. Therefore I see no value in costly enzyme tank additives.
To help prevent future clogs always keep the black tank valve closed. Don’t empty the tank until it is at least 2/3 full. If it isn’t 2/3 full, add water until it is. After each dump and rinse, close the valve and add enough water to cover the bottom of the tank. The first few times you flush solids use extra water to flush the solids away from under the toilet. As the tank fills you can use less water to flush to increase the time between dumps.