Questions on buffer tanks

Hey guys, so I have a few questions, on buffer tanks.
and what is considered common practice to have on a trailer. So I know when you have a 12v system for roofs you have one buffer mix tank lets say 65 gallons. Correct me if I’m wrong but most trailers usually have at least one second tank filled with SH. Is it common practice to have a large holding tank for strictly water? Or do you just use the customers water?

Question #2 obliviously on a 12v system the pump pulls the water/solution from the holding/buffer tank. Let’s say your useing a 4GPM PW and are DS washing a house can you use a buffer tank/ holding tank for a water source or does a PW need to be hooked up to an actual building water source?

If it’s a 4gpm then you don’t need a buffer tank, just hook up to the house.
Use your tank for roofs and for DS.

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I live in an area that has a lot of wells so the water pressure may not be great. If you can’t hook up to the customers water source can you pull straight from a holding tank at a rate of 4GPM?

I just did an old house yesterday that wasn’t putting out 4gpm. My 4gpm was draining the buffer tank, I’m sure glad I had it so I didn’t ruin my pump or have to turn down a job. My thoughts are if you can fit one get one, but realize you don’t need a 300 gallon buffer tank. Keep it small. I use a 65gallon, probably could have gone smaller but it was too good of a deal to pass up.

You’ll be bummed the day you have to turn down a job because you don’t have a buffer and the house supply isn’t enough.

If u have belt drive it will pull from the buffer tank.

All u need is a water valve with a float on ur buffer tank to keep u from running out of water and messing up ur pump. If ur running a small buffer tank like a 65gal I would recommend u getting one.


Terminology: A 65 gallon mix tank is referred to as a mix tank, not a buffer mix tank.

Most trailers that have a pressure washer and a 12V pump will carry a large buffer tank (water) and smaller mix tanks. The type of mix tanks depend on what methods they are using to clean houses.

If you clean houses by downstreaming, a common configuration is 1 buffer tank (50-250 gallons depending on need), 1 roof mix tank (50 gallons or more), and 1 downstream tank (5-15 gallons).

If you use a 12V to clean houses with, you might find a house mix tank, and a roof mix tank. Both will need to be fairly large (50 gallons or more).

SOME guys carry a tank of straight SH with them, and use it to make their mixes on site, or use it with a proportioner on-demand system. Some make the mixes at the shop, and only roll with the mixes, or might bring a smaller container of straight SH (5-10 gallons).

Like others have said, whether you need a buffer tank depends on the general water supply in your area, how big of a machine you have, and how many pumps/machines are going to be using water at once. If you only have a 4 GPM pressure washer, you might not need one, and if you do, a 55 gallon drum is plenty. 55 gallon drum might work for higher GPM machines as well… just depends on the circumstances.


Either. You can hook straight to the spigot, or pull from a buffer tank, to use a pressure washer. There are three main types of pressure washer pumps… direct drive, gear drive, belt drive. Gear and belt drive pull water the best. Direct may have issues pulling from a tank, although some report that it works ok.


I have the same issue here. Very rural area not everyone as enough water pressure to feed even a 4gpm machine. I have a 125 gal buffer tank for my pressure washer. Works well, just have to get all the air out of the suction hose to create enough siphon to feed the machine. PW should also be belt dive, not direct drive.

You should only have to purge the system of air on the initial install or if you run completely out of water. Any other time indicates an air leak.

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Is this a box truck or pull enclosed trailer?

Its a box truck. This is a picture from the beginning of the year when I was setting it up.

Just walked in the door from a turned down job. It was a friends house, so I didn’t go out before hand like I normally would. I literally could pee more pressure than his hose put out. He just moved in so he didn’t know yet either. Can’t wait till next season when I have my upgraded equipment and a buffer.

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This isnt always the case I have a 4x4 machine and worked on a house this past weekend pushing 2gpm water if I was lucky.