Wastewater Tank Cleaning
Every RV'er knows about holding tanks.
An RV with holding tanks is also known as a self-contained RV because you carry fresh water and have black and gray tanks to hold your waste water until you can dump your tanks at an approved facility. Like most things in the RV world, it pays to know your system and take care of it to prevent expensive problems.
Consider watching these two videos on Youtube that discuss cleaning and treating your holding tanks in more detail:
RV holding tank cleaning, maintenance and tips with Sue from Royal Flush RV! - YouTube
Top 2 RV Black Tank Treatments put to the test! Unique vs. Liquified - YouTube
Preparation:
Your tanks must be empty before they can be cleaned. You must also have a sewer dump at your RV. That normally means you must be parked in a campground with full hookups.
Background:
Technically, you are not required to add any sort of ‘treatment’ to your holding tanks. Many people will add commercial treatments to help take care of odors and help break down the tank contents. If you plan to add any sort of extra treatment to your tanks, avoid anything with harsh chemicals, especially formaldehyde. Many campgrounds and RV parks will have strict rules about chemicals in their septic system because they depend on chemical free waste water for efficient processing of the waste. There are many effective holding tank treatments that do not depend on harsh chemicals.
Generally, you should never leave your dump vales open when you are connected to a campsite sewer dump. The only time you should open the valves is to dump your tanks when they have enough water in them to flush out the contents. Otherwise, leave them closed until you accumulate enough water. If you need to dump your tanks before a travel day, and they don’t have much water in them, add some water to provide that needed flush of the tank.
One exception to this advice is when you know you are going to add a lot of water in a short period of time. For example, if your RV has a clothing washer and it is laundry day, you will need to open the gray tank valve so the waste water from the washer doesn’t overwhelm your holding tank. Once the laundry is finished, close the valve again.
Please note that not all RVs have holding tanks that can be easily cleaned. For example, motor homes with a macerator installed in the system cannot be cleaned without removing the macerator. Some 5th wheel RVs have long runs of pipe and several 90 degree bends in the pipe that will also prevent access to the tank.
How often you should consider having your holding tanks cleaned depends on how you use your RV. If you are someone that uses lots and lots of water to flush your tanks, you might get away for years before you have a problem. Otherwise, you should consider having your tanks cleaned annually if you use your RV frequently or full time. If you tend to stay in one place for months at a time, your holding tanks are likely in need of a good cleaning because of accumulating waste that hasn’t been effectively flushed.