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How to Connect a Dishwasher to Water Supply Step By Step

how to connect a dishwasher to water supply

Have you just purchased a dishwasher? Well, congratulations! You will no longer worry about the utensils piling up in the sink. All you need to do is toss the dirty dishes into the dishwasher, and it will do the rest for you. However, for your dishwasher to work, it needs a supply of water (preferably hot water) to clean the dishes thoroughly. Fortunately, connecting your dishwasher to a water supply is a simple process that can be done by yourself without hiring a professional plumber. In this article, we will give you a step-by-step process of how to connect a dishwasher to water supply.

Tools needed:

Step 1: Shut off the Water Supply and Disconnect Power

Before you start the installation process, the first thing you need to do is turn off the main water supply. This will make the installation process easy and stress-free. You also need to disconnect the dishwasher from power to prevent electric shock when connecting the dishwasher to a water supply. Failure to do so can result in electrical shock which may cause death. If you are not confident to do this job you can take service from Lex’s plumbing.

Step 2: Verify Compatibility

Ensure the hot water supply line connection configurations complies with the local cords and regulations. If not then the 3/4 by 3/8 inch hose fitting may not fit perfectly on the dishwasher valve and copper pipe respectively, thus causing leakage.

Step 3: Connect Hose Fittings

The next crucial process is installing the 3/4 by 3/8 inch hose fittings, which the standard for the dishwasher. Do this, remove the dishwasher from the cabinet then identify the hot water supply pipe. This pipe is usually made of copper and protrudes just beneath the sink. If the copper pipe has a valve, use an adjustable wrench and pliers to remove it from the copper pipe, clean the hot water copper tube with a clean cloth to remove any dirt and debris that may hinder the smooth flow of water. Once you are done, install the valve back then connect the hose fittings. If you want to make your dishwasher more flexible, you can connect an additional pipe into the copper pipe.

Step 4: Install the Nut and Ferrule

Before you install the 3/8 inch hose fitting, gently slide a nut and ferrule into the copper pipe. Start with the nut follower by the ferrule about 2.5cm into the copper pipe. Ensure that the water does not touch the base frame of the dishwasher or motor to prevent vibration when the dishwasher is operating.

Step 5: Insert Water Supply Line

Gently insert the water supply line in the standard 3/8 inch compression fitting as deep as it can go to ensure that there is no leakage. At the same time, ensure that the 3/4 inch hose faces upwards. Gently insert the rubber washer on the 3/4 inch hose fitting. Please do not use Teflon tape because it may loosen the compression fitting, causing leakage. Tighten the nut and ferrule by gently moving it in a clockwise direction until it fits tightly into the 3/8 inch compression threads. Use an adjustable wrench to fit the nut tightly. Remember that copper tubing kinks and bend easily. Therefore, when tightening the nut, you need to be as gentle as possible.

Step 6: Align the 3/4 Hose Fitting With the Dishwasher Valve

Align the 3/4 hose fitting with the dishwasher valve. Don’t use the adjustable wrench to tighten the coupling. Instead, tighten using your hands to prevent cross-threading. Use the plier to check the tightness of the coupling. If it has not tightened, turn it slightly using a plier until you are certain that the rubber gasket is fully sealed to prevent leakage. Do not over tighten to prevent tripping the treads, thus causing leakage. Be very gentle when tightening the connectors.

Step 7: Test if the Installation is Watertight

Test if the installation is water-tight by placing a paper towel under the 3/4 by 3/8 inch hose fitting and check if leaking occurs. If there is a leakage, you need to tighten both the 3/ 4 and 3/8 hose fittings again until there is no leakage.

Step 8: Turn On Hot Water Supply and Power Supply

Return the dishwasher into the cabinets, then turn on the main hot water supply and power supply.


Whether you are using a double drawer dishwasher, single drawer dishwasher, or a countertop dishwasher, connecting the dishwasher to a water supply is a simple and straightforward process that you do on your own by following the simple steps given above. All that is needed is having the right installation tools and being gentle, especially when connecting the 3/4 and 3/8 hose fitting to the dishwasher valve and copper pipe respectively. If you have the right installation tools, the entire installation process will take you less than one hour to complete.

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