A dirty RV project: Dumping wastewater tanks on a farm

We can normally boondock for about two weeks before our 50-gallon black water tank (toilet waste) fills up. While moochdocking at my cousin Deb’s in Michigan, however, our black tank appeared to reach capacity after only a week and a half — even though Bob had been out of state for about half that time — necessitating a dirty RV project. 

Measuring full

During our first year as full-time RVers, Bob installed after-market tank-level monitors on our black tank and freshwater tank to give us a realistic picture of the volume of their contents. (The factory gauges that come in most RVs aren’t reliable, indicating full tanks when they’re not.)

After five years of use, our after-market tank-sensor monitor started giving us false readings: 100% freshwater and 0% black, both of which we knew were incorrect. Bob returned the monitoring unit to the company, Tech-Edge, which troubleshot and fixed the issue — two burned-out chips on the circuit board — and sent it back to us.

Once Bob reinstalled the refurbished monitor, we got a reading that our black tank was at 90% capacity. We took measures to minimize adding to the black tank, but the next day, the monitor read 100%. We had to empty it. 

We hadn’t planned to move our rig for another three days and didn’t really want to close it all up, move it to dump the tanks, and then reset it up for just a few days. In previous years at the farm, we had a company pump out our black and gray water tanks. This year, though, they wanted triple the price.

Taking a dump

Fortunately, Deb’s son also owns an RV and had a portable holding tank we could use to transport the contents of our black and gray tanks to a septic tank on the farm. It sounded simple enough. The problem was that the portable tank held 36 gallons, which meant we’d have to stop draining our black tank before it emptied to prevent overfilling the tote tank. 

To be safe, we decided to start with one of our two gray tanks. Together, the kitchen sink tank and the bathroom tank hold 85 gallons. Deb offered to help and arranged for a forklift driver to transport the filled tote tank to the septic tank for draining. He brought over a pallet on a forklift, and Bob and Deb put the pallet into position to pull the tote onto once it was full. 

Typically, we empty our tanks with the trailer slideouts closed for easier access to the trailer sewer dump pipe and tank levers. Since we weren’t moving the rig, Bob, with gloved hands, disappeared under the office slide to connect the sewer hose to the drain pipe. Deb, also gloved, held the other end of the hose in an opening on top of the tote tank. I watched, took pictures, and helped where I could.

They successfully emptied the kitchen gray tank into the tote with only one minor mishap of the hose coming out of the tote very briefly. Good thing we started with the gray water! Bob and Deb pulled the tote onto the positioned pallet, but there was no sign of the forklift driver. He had gone to lunch. We didn’t want to wait an hour for him to come back. 

Toting sewage

The tote came with a tow handle that could connect to a trailer hitch ball. So we attached the tote to Gulliver and climbed inside. I made sure Bob and Deb removed their gloves before getting in. Bob drove very slowly the 50 yards or so to the septic tank, watching the tote follow in our rear cargo camera.

Shortly before reaching the septic tank, the pin connecting the handle to the tote fell out, leaving the tank in the middle of the dirt road. We reattached the handle, and Bob and Deb dragged the tote into position to empty it. They donned gloves again (we went through a lot that day), removed a round concrete lid covering the septic tank hole, connected a sewer hose to the tote, opened a lever, and let the substance go. Success!

Next came emptying the black tank. We were able to stop the flow out of the tank in time to keep from overfilling the tote — with no hose mishaps. This time, the tote stayed attached to the truck, and Bob and Deb emptied its contents smoothly, as they had with the first gray tank. 

Back at Tagalong, we finished emptying the black tank into the tote, which still left plenty of room. So we drained the bathroom gray tank into the tote and filled it pretty full. Then we repeated the emptying process. We were able to dump all three of our tanks in only three trips.

Looking back, we’re convinced all the contents of the black tank would have fit in one tote tank full, which means our sensor wasn’t working properly. We still had at least another 10 gallons of space in the black tank. It’s always better to err on the side of caution, but it would be nice to get an accurate reading. Bob will have to recalibrate the sensor. It likely got off during the repair.

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