---
title: Pressure Washer ECU, What & Why | Hydro-Chem Systems, Inc.
description: The cleaning efficiency of a pressure washer is calculated using the formula (PSI x GPM).
---
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## What Is The ECU Of A Pressure Washer, And Why Is It Important For Touchless Vehicle Washing?
May 06, 2017
by [Hydro-Chem Sales](https://blog.hydrochemsystems.com/author/hydro-chem-sales)
How much PSI and GPM are required to get your job done properly and efficiently? The cleaning efficiency of a pressure washer is calculated using the formula (PSI x GPM). This simple equation yields E.C.U. which stands for “effective cleaning units” this value is an excellent proxy for the true cleaning power of a pressure washer. Most people only consider pressure and disregard the equally important GPM component of the pressure washer pump.
Pressure is expressed in pounds per square inch (PSI) and describes how much water pressure per square inch the unit delivers to the surface being cleaned. PSI is important to break the bond between dirt or grime and the surface. Some bonds are much more difficult to break than others.
The water volume, also known as the GPM of the unit, is measured in gallons per minute. The GPM is the amount of water being applied to the surface being cleaned. This is also referred to as the “flow rate”. The GPM of the washer is critical to the time it takes to clean a surface. With a sufficient PSI for bond breaking a washer with a higher GPM will take far less time to clean than a lower GPM unit.
Most applications rarely need more than 3,000 PSI. A few years ago many contract cleaners were taking the ‘Tim Allen’ approach and purchasing 3,500-5,000 PSI units. Today they are opting for units with 2,000 to 3,000 PSI and a much higher GPM. This is because the bond of the dirt being cleaned can be broken from most surfaces fairly easily utilizing “bond breaking” touchless soaps but must then be quickly washed away. In these instances Time really is Money.
Hydro Chem Systems, Inc. has been a leader in touchless cleaning for over 30 years. We consider ourselves cleaning consultants because we work with the customer to determine the soap needed and the proper application to get the job done in as little time as possible. If you are interested in hearing how you can have a touchless truck wash by using a time tested truck wash system please contact us. We stand ready to serve you.
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