How To Build a Soft Wash / Roof Wash System Under $500

One of the most common questions I get from people just starting out in pressure washing is about soft wash systems. They see the professional setups that cost thousands of dollars and think they can't get started. That's not true. You can build a fully functional soft wash and roof wash system for under $500, and in this video I show you exactly how to do it.

It only takes a few minutes to assemble if you've got some basic experience with plumbing fittings. And once it's built, you can start offering roof cleaning and house washing services right away — that's where the real money is in this business.

Why you need a soft wash system

Soft washing is different from pressure washing. When you're cleaning a roof, you can't blast it with high pressure — that'll blow granules off asphalt shingles and void warranties. Same thing with certain types of siding, stucco, and painted surfaces. You need a system that applies cleaning solution at low pressure so the chemicals do the work, not the force.

A soft wash system lets you pump your bleach solution through a hose at low PSI, spray it onto the roof or house, and let it dwell. That's the whole concept. And the equipment to do it doesn't have to cost you an arm and a leg.

The core components of a budget soft wash build

Here's what you need to put this system together. I keep a full parts list on my website at kingofpressurewash.com so you can see every item and where to get it.

The heart of the system is a 12-volt pump. I use the Delavan series pumps — they're reliable, affordable, and built for this kind of work. You'll mount this pump to pull chemical from a drum or tank and push it through your hose out to the roof or house.

You'll need a drum or tank for your chemical solution. A standard 15 or 35 gallon drum works great for getting started. You don't need a 200 gallon tank on day one. Start small, prove the concept, and reinvest as the jobs come in.

Garden hoses connect from your tank to the pump and from the pump out to your spray tip. That's right — regular garden hoses. You don't need fancy high-pressure lines for soft washing because you're running at low pressure. The fittings, barb connectors, and hose clamps to connect everything cost just a few dollars each.

Assembly is straightforward

In the video I walk through the entire assembly process. You're basically connecting a hose from the bottom of your chemical tank to the inlet side of the pump, then running a hose from the outlet side of the pump out to your spray gun or nozzle.

Add a switch to power the pump on and off, wire it to a 12-volt battery, and you've got a working system. The pump does all the work — pulling the solution from the tank and pushing it out through the hose with enough pressure to reach a two-story roofline.

The whole thing can be mounted in the back of a truck or on a small trailer. It takes up barely any space, and you can build it in an afternoon.

What does this system let you do?

With a soft wash setup like this you can offer roof cleaning, house washing, fence cleaning, and any other soft wash service. Roof cleaning jobs alone can range from $300 to $800 for a typical residential home, depending on your area. It doesn't take many jobs to pay off a $500 investment.

This is also the same basic system I use for applying chemicals to houses when I'm doing house washes. Instead of relying solely on a downstream injector on the pressure washer, you can use the soft wash pump to apply a stronger mix directly to really dirty surfaces.

Upgrades you can make later

Once you've been running this basic system for a while and the money starts coming in, there are upgrades that make sense. A bigger tank lets you carry more chemical without refilling. A higher-GPM pump means faster application. Better spray tips give you more range and a more even pattern.

But none of that is necessary on day one. The point of this build is to get you in the game. Start earning, prove to yourself that the demand is there, and then reinvest in better equipment as your revenue grows.

Frequently Asked Questions

How much does it cost to build a soft wash system?

You can build a fully functional soft wash and roof wash system for under $500. The main components are a 12-volt pump, a chemical tank or drum, garden hoses, fittings, and a battery. As your business grows, you can upgrade to larger tanks and higher-output pumps.

What pump do I need for a soft wash system?

A 12-volt Delavan pump is a popular and affordable choice for beginners. The Delavan FB2 series (60 PSI, 7.0 GPM) is commonly used for roof cleaning setups. It's reliable, affordable, and has enough output to reach two-story rooflines.

Can I use a soft wash system for house washing?

Yes. A soft wash system works great for applying chemical to houses, especially when you need a stronger mix than what a downstream injector on a pressure washer can deliver. Many professionals use their soft wash pump for both roof cleaning and house washing.

What chemicals are used in soft washing?

The primary chemical is sodium hypochlorite (bleach), mixed with water and a surfactant. The bleach kills mold, mildew, algae, and moss. The surfactant helps the solution cling to surfaces and not run off too quickly. Different surfaces require different mix ratios.

Is soft washing better than pressure washing for roofs?

Yes. High-pressure washing can damage roof shingles by blasting off the protective granules, which shortens the roof's lifespan and can void warranties. Soft washing uses low pressure and chemical to safely remove organic growth without causing damage.