What size pressure washer do I need to clean concrete?

Cleaning grimy concrete surfaces such as patios, driveways or garage floors no longer takes countless hours of hard work. A pressure washer can do the job in a fraction of the time and will make your outdoor spaces look like new.

But a power washer is a serious piece of equipment. It forces a stream of water out of a nozzle at more than 60 times the pressure of a regular garden hose, making it important to choose the right model and use the best techniques to get safe, superior results.

Pressure washers are available in both electric and gas-powered models. Electric models can cost as little as $150 and require less maintenance, but they are also less powerful and may not produce enough pressure to clean some hard surfaces. Most electric pressure washers create 1300-1700 pounds per square inch of pressure (PSI) with a water flow of 1.5 gallons per minute (GPM), but experienced contractors recommend between 2000 and 3000 PSI and a flow of at least 2.5 GPM to clean dirty concrete effectively.

Gas-powered models come in several sizes for home use. Small models average 2000-2800 PSI and up to 2.8 GPM while larger models are capable of 3000-4000 PSI and more than a 4 GPM flow. With pressure washers, more isn’t always better. Power washers can damage some hard household surfaces, so when evaluating models consider your needs carefully. Ask the professionals for tips. At double the price of a small gas washer, a large unit may be much more than you need.

A small gas-powered pressure washer is a good bet for many household cleaning jobs including concrete. Larger washers clean concrete faster, but are too strong for most other cleaning applications. Some homeowners buy an electric model for routine cleaning and rent larger washers as needed.

When selecting a power washer, be sure the right nozzles and accessories are included or available for purchase separately. To clean concrete, you will need a high-pressure nozzle for a fine, strong spray, a wide-angle nozzle that sweeps for rinsing and a low-pressure nozzle to apply detergent.

Before you get started, talk to a professional if your home is on well-water or a low-pressure municipal supply. Pressure washers depend on a sufficient inflow of water to work and if your home water pressure is too low, the washer may be ineffective and could be damaged during use.

To pressure wash concrete:

1. Read the manual. Gather tools and safety gear and set up the washer.

2. Clear the surrounding area. Lay protective coverings over sensitive surfaces. At 2000-3000 PSI, a mid-size pressure washer can cut skin, strip paint off surfaces and damage wood.

3. Begin the process at the highest point so water will drain away from your surface.

4. Brush or spray loose debris off the concrete.

5. Apply detergent with a low-pressure nozzle and let it process per the manufacturer’s directions. For motor oil stains, look for soap with degreasing agents.

6. Rinse the surface and let it dry. Repeat as needed.

You’ll be done in no time. When you’re through, break down your washer and perform any required maintenance. Then grab the kids, head to the park and enjoy the rest of the day knowing you’ll return to a clean home.