5.5 or 8 GPM

I’m building a new machine and I was ready to get a 8 gpm and put it on Honda690. I plan on using it mainly for residential. Some have suggested that I might be better off with a 5.5 It would let me use a smaller buffer tank And for residential would Not be that big of a differences as far is time what do you all think Is more useful?

Depends I have both and love the 8. If I had to choose one I’d go with the 8. It’s better for flatwork (concrete) because it’s faster.


Thanks just trying to get some other ideas

I think a lot of it depends on your entire trailer, your areas water flow, and what you’re going to be doing with your business… firstly if your area has good water flow you can probably get away with a smaller buffer tank and the 8gpm. The bigger the better for a buffer tank but if you’re trailer just isnt big enough then you can make a smaller one work. If you’re going to be doing mostly houses and concrete (which most of us do) you’d probably rather have the 8gpm but if you’re doing a bunch of wood fences and decks a lot of people prefer the 5.5gpm for that.

1 Like

I worked my way up to an 8 the past two years.

5.5 is ok, does the job. I had it for a year and one advantage is the injector draws better than the 8. Rinsing and surface cleaning are decent, but height isn’t all that especially in a stiff breeze.

8gpm shocked me. I was able to hit a three story peak no problem with a shooter tip and 12” wand. Surface cleaning is much faster, rinsing is like a fire hose. However the bleach percentage is considerably less so now I either go over the bad spots three times or break out the 12v.

As for buffer tank, believe it or not I’m still using the 55 gallon I started with. On a decent home tap I rarely see it get close to empty, unless I’m on the surface cleaner and rinsing driveways. Even then it gives me an excuse for a break.


Like others have said, it depends on what you are going to do (and I’ll add the MAJORITY of your work). If your doing concrete some house wash stuff and some industrial stuff 8gpm is king. If your doing decks, I think an 8 is too much and I own and use an 8. I would think 6gpm would be great for decks but I don’t have an apple to apple comparison. I think it floods the area around the deck while rinsing. You have to rinse twice, and sometimes you spray additional water to keep your chems wet.

I’ve run my 275 gallon buffer virtually dry before doing industrial work with a slow water supply. I don’t know how these guys do it (never running empty). You’ll instantly know if your far away and your too low on water, it starts pulsing.

Sorry, I didn’t start with good luck to you. Brain started firing.

Thank you I appreciate being able to learn from your experience.

I have an 8 and while I love it, I question the overall efficiency benefit compared to a 5.5. As said earlier, if you deal with tall heights, stiff wind, and you eirher have access to good water flow or have no problem hauling 300 gallons everywhere like I do, and you don’t mind bleaching many times over or setting a soft wash system for bleaching, go with the 8.

If you have limited water feed rates and you are doing 1 and 2 story homes without much wind, maybe look jnto the 5.5. The 8 is awesome, but I made my first $55,000 with a 4 gpm. It’ll be quite a bit simpler than having an 8 gpm plus soft wash or whatever.


I agree, think he should go with the 5.5 and learn to maximize that first. Can effectively clean just about anything you need to for less money, especially when you figure all the additional costs, if you’re just starting out. If the business is there and learn to use it, can pay for an 8 pretty quick if needed in the future.


This thread answers any question I may’ve had about going with a bigger machine. I live in the country, and here in Western Kentucky, water pressure is iffy. I’ll stick with my itty bitty 4gpm machine. I don’t do enough washing to justify a move up.

Probably a good move. I am in rural Ohio, and I used a 4 for 2 years. I will say though, the 8 gpm is so much faster that hen I use my old 4 gpm for the hotter mix (with jrod) I cant decide if the machine is breaking down or if the power was always so low and I just didn’t notice it before using the 8.

1 Like

Why can’t people just use a 2-3 gpm injector on the 8gpm machine and then use a bypass to rinse with for hotter mixes? I use the 5-8 gpm Nozzle on the injector and it works fine when DS straight 12.5%. I like that injector nozzle size because the rinse is just as fast as if it wasn’t bypassed (at least using the @SchertzServicesLLC box). If you need to clean something worse then 12v it…

I have both on my trailer. My 8gpm has 1100 hours and my 5.5 has 15. I have a 225 gallon buffer (usually half full at the beginning of jobs) and only wait for water on a few jobs. I would rather wait for water 5% of the time and wash faster the other 95%. The cost savings is negligible.