Van Sink Waste Adapter
Connect this sink waste adapter to your sink waste from under the sink. This reduces the the 50mm standard plumbing required in house sinks to 20mm.
Take it one step further - fit a 25mm grey water waste hose over the 20mm sleeve of the fitting. Secure the waste hose using an adjustable hose clamp. Run the other end of your waste pipe and connect it into a grey water tank and BOOM! You just did some plumbing!