Buffer Tank Flow Rate (Video)

I have all the plumbing done on the new power wash trailer and I did a quick check to make sure the tank will supply enough water to my two machines. I’m running two, 4.5 GPM pumps so I need at least 9 gal per minute. I think I’m covered based on the test I did today. Here’s a short video:


That’s some awesome hose isn’t it. I run water thru the coffee maker and put the end of the hose in it for a minute to soften it before sliding it on the barb

It’s terrific hose. Thank you for recommending it. I just slipped it on the end of the barb for this test. I feel better now knowing that the tank can handle both machines and my future upgrade to 12 GPM.

Anything more than what you have now be sure to run a separate line to each machine. Bung hole fittings are cheap so don’t be afraid to drill holes in the tank where needed. All my tanks have 3 holes at the bottom. One for each machine and a drain. Looks good.

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I was actually wondering about that. Thanks for the clarification, it makes perfect sense.

Sorry about reviving an old thread but i am using my resources and using the search function. This is all gravity fed and no pump correct? Im considering adding a buffer tank to my 4gpm direct drive but have read all the skepticism of direct drives and gravity fed systems. Does the flow dramatically reduces as water level decreases in the tank?

No. I’ve never had any problems with it. I hooked a buffer tank to my 4GPM direct drive before I had ever heard anybody say that it wouldn’t work. In fact I had been using my 4GPM direct drive with a buffer tank for several years before I actually heard people say that it couldn’t be done. Lol

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When I first started in 2018, I had a 4/4 and was rolling it out of the trailer so it would be below the buffer tank, and it worked pretty well.

I got fed up rolling it out every job so I plumbed it inside the trailer, so the water line was parallel with the tank. It worked decently enough if I had a full tank (55gal) but the pump got to where it didn’t sound too happy about it, making a “grrrr” sound.

I got a 5.5/3500 belt drive in 2019 and solved that issue.

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I too use to run direct drives off buffer tanks when I first did a trailer build. Even a lil 3.5 gpm Home Depot machine will pull, so long as enough water is in the tank to push it. Mine had about 5-7 feet of hose from the tank to the machine. I will say though, when doing driveways like that, the sc would run slightly faster when hooked directly to the spigot.

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Thank you everybody. Once i get my buffer tank setup i will do the same 5 gal bucket test that steve did to test out pressure. Ty again for the help