This article appeared in the January/February 2019 issue of the RV Women Magazine and is reprinted with their permission. To download a PDF of the article, click here.

Donna Parker, a member of the Texas Ramblin’ Roses Chapter, attended a seminar at the Shawnee Convention that was so helpful she recently shared the information
in the RVW Facebook page that is for members and non-members.

Preston Hall, who started All Pro Water Flow, has presented at several RVW conventions. His presentation on Common Sense Holding Tank Maintenance at the recent Shawnee convention included information about an inexpensive, non-chemical “recipe” to use for your gray/black holding tank treatment. Many of those commenting on Donna’s post said they had been using this same recipe for years, and were very pleased with the results.

The following is from Preston’s website at

During your trip:

  1. Always filter incoming water to your RV (bad water will hurt everything)
  2. When camping, keep both black and gray valves closed
  3. Never empty tanks that are less than 3/4 full. It is ideal to empty your tanks when they are full.
  4. If possible, top off both black and gray tanks with clean water before emptying
  5. Always start off with a small amount of water in your tanks (NEVER start using your tanks when they are dry)
  6. Always use single-ply paper in RV’s and boats

After your trip

  1. When possible, drive home with your tanks 1/4th full and dump at your local dump station (this allows your tanks to “stir” themselves while you’re
  2. Store your sewer hose as clean as possible
  3. If you winterize, always add a little RV antifreeze to your tanks (helps lube gaskets and valves)

“Recipe” for the All Pro Water Flow Tank Solution
Mix up a gallon of this solution to use in both your black and gray tanks while you are RVing. It will keep the internal surfaces of your RV’s holding tanks slippery (reduces build-up), sanitizes the tanks, and has a nice, fresh smell.

  1. Start with an empty gallon jug
  2. Pour 1/4 cup (4 ounces) of Calgon Bath Beads (or liquid) into the gallon jug
  3. Fill the jug 1/2 full with water. Shake well.
  4. Slowly pour 40 ounces of Pine-Sol into the jug. Shake well.
  5. Top off the gallon jug with water. Shake well.

Use 8 ounces (one cup) in your black tank(s) and 4 ounces (1/2 cup) in your gray tank(s) each time, after emptying and backflushing.

Donna added that Preston told convention-goers they actually don’t have to use this treatment every time. Once you get it started, you can treat about every third dump. Some of those commenting said they use Dawn dish soap as part of a holding tank treatment. He discouraged the use of Dawn due to the buildup of bubbles.

Donna said he explained the water softener component of the recipe treats the tank as you use it. Waste floats up and slides out with water pressure. Slip and slide! She also said he told those at the seminar that the cup you add to your black tank and 1⁄2 cup to your gray is not a precise measurement, just eyeball it as you pour it into the toilet, sink and shower drain.

For more information on tank cleaning and care, visit Chapters may also want to have someone from his company speak at a rally.

Preston Hall, a master plumber and RVer, is the founder and owner of All Pro Water Flow, an RV holding tank service that cleans and sanitizes tanks. He presented a seminar at the 2018 Shawnee Convention and is a long-time supporter of RVing Women.