How to instructions for semi-permanently installing a countertop dishwasher.
DISCLAIMER: For informational purposes only. You should definitely not do this.
So you've bought a countertop dishwasher because you live in a city with old buildings and landlords who refuse to invest in improving the day to day lives of their tenants. You place an order with Amazon or Walmart, patiently waiting for the delivery person to arrive and deliver you freedom from dish cleaning with the added environmental benefits of using far less water in the process. The box arrives, you carefully open it, and notice that instead of providing you a convenient method for connecting your dishwasher's water line to your kitchen sink, the manufacturer has sent you this weird contraption that requires you to replace the aerator with a quick connector, and a jumble of hoses that is really messy. You ask yourself, why can't I just connect the inbound water line more permanently to the faucet, perhaps using a diverter to conveniently switch the water from the sink to the dishwasher. Seems easy enough you think, so you spend hours scowering YouTube, thoroughly amazed with the lack of definitive instructions on how to do this.
If the above situation describes you, you're in the right place. The key issue with connecting a countertop dishwasher to a faucet diverter is the utter insanity of the connector choices made universally by the manufacturer. You would assume that a standard universal dishwasher installation kit could get the job done but unfortunately its a bit more complicated than that. The underlying issue is that dishwasher supply lines typically are shipped with an elbow garden hose threaded 3/4" female adapter that you connect to standard dishwasher intake valves, while countertop dishwasher almost universally use 3/4" male pipe threaded intake valves. To connect these you need an adapter.
There are a lot of ways you can do this, but our hypothetical case above, our protagonist chose to first use a VC Threaded 3/4 Inch Female Pipe Thread x Hose Thread - Swivel Hoses to Pipes, Adapter Fitting to convert the dishwashers pipe threaded input valve to ght. The rational here was to avoid a direct metal thread connection to the dishwashers plastic threads. Our protagonist isn't a plumber, but this seemed like a safe bet. Next a 3/4" male to male GHT brass coupler can be used to allow you to connect the 3/4" in FHT elbow connector provided with most dishwasher kits to the supply line. Congrats you're half way there!
Now that we have a supply line, its time to connect it to our faucet. Our protagonist used this faucet diverter to allow one to easily switch between supplying water to the dishwasher and using the faucet. The universal dishwasher kit included a 3/8" inch to 1/2" connector that could be used to directly connect the supply line to the diverter.
Oh and since our protagonist failed to mention it above, be sure to use teflon thread tape on all the threaded connections, even the compression fittings to be safe!
Once you have the system setup, now its time to test. First run the fauce, ensuring water runs into the sink, and that there are no leaks at any of the junction points between the faucet and the aerator. Next divert water to the dishwasher. Inpect each junction of the system between the sink and the dishwasher, and tighten these connections if you find issues along the way. This step can be painfully time consuming. Finally our protagonist suggests running the dishwasher for a full cycle, ensuring that you don't detect any slow leaks.
Congrats now you have a semi-permanently installed countertop dishwasher!
While in theory you could plumb the countertop dishwasher's drain directly into your sink's drain pipe, this would most definitely violate your lease and upset your landlord. If your sink has a disposal, you may get away with the easiest option which is to simply place the drain line that is supplied with your dishwasher into the disposal. You should really only do this if your disposal has a splash guard, since the supplied drain line is only a 1/4" wide, resulting in the water exiting the line with significant pressure that can cause the discharge water to splash out of the sink. An alternative solution is to purchase a standard universal dishwasher drain hose. Attach the 3/4" rubber stub (intended to be connected to the sink) to the dishwasher and clamp it down tightly with the include clamps. You may want to use thread tape on the dishwasher's threaded discharge valve to help prevent leaks. Finally, you can cut the hose down to the desired length using an exacto knife.