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Question:

I pump from the bottom of my truck’s tank through a 3-inch gate valve. If I pump a tank and use, let’s say, 75 feet of hose, when the septic tank is empty, I have a little under the 75 feet worth of liquid caught into my suction hose. Even though the pump is still pumping it just sucks air and leaves this liquid trapped in the hose. So in turn I have to disconnect from the truck (with the valve closed of course!), and drag that end to the septic tank and pour what is sitting in this 75 feet of hose back into the tank.

I know physics and gravity are at play here, and I was wondering what an option might be. I’m tired of dragging these heavy liquid-filled hoses around, and then have the customer frown when I have to put some of the liquid back in the tank. It has really made my job miserable and doesn’t make me look very professional. The mess all over the bed of the truck is always an issue too.

I was thinking about a shut-off valve at the end nearest the septic tank, but would that just vapor-lock and leave the liquid there? Or would it actually clean out what is left in the lengths of hose?

Answers:

The only time I get a hose full of liquid is when I fill the truck and have the primary shut-off kick in. Otherwise the hose gets sucked fairly dry. Now to get the last of the gunk out of the hose, I suck up a 5-gallon bucket of clean water while I still have good vacuum. This keeps the hoses clean. If I have to drain back to the tank, I make a 5-foot loop and walk it back to the tank. If I have a thick and heavy tank I will walk the loop to the truck and then wash out the hose.

Something’s wrong here. You should be sucking your hose dry. Maybe you are losing vacuum when the septic tank is empty? Try closing your gate valve for a minute to build up vacuum then open quickly to suck your hose dry. I do this a couple of times to make sure hoses are clean.

It would be better if you pumped into the top of the tank and not through the liquid already collected. As already mentioned, close the valve and let some vacuum build up. This might take a minute or two depending on how big your pump is, how much hose you have out and how much liquid you have in the tank. Then quickly open and close the valve. You may have to do this a couple of times to get the desired results.

Look around when you pull up to the customer’s residence to see if they have a garden hose handy. This isn’t always an option, but it works well to clean out your hoses while still pumping. Also, walk back along your hoses while draining them toward the truck while still pumping.