For optimal functionality when installing or renovating a kitchen sink, having the optimal drain height is critical to its success. This includes providing ample water flow while cooperating with any under-sink plumbing lines as well as helping prevent future clogs and leaks.
Your sink's drain height depends on the size and location of its drainpipe from its connection with the main sewer line to its P-trap under your kitchen sink. Usually this pipe measures 1-1/2 inches in diameter but may differ depending on local building codes, sink type or other factors.
Before purchasing a drainpipe replacement for your sink, measure the current height of its trap arm (the horizontal piece that extends down from the sink bowl towards the P-trap). An optimal height would be 16 inches from either the floor or bottom of your cabinet; this allows your P-trap to slope downward at about 1/4 inch per foot to avoid wastewater pooling in its pipe and clogging your sink.
Adjust the drain height without taking down your entire sink by using an extension tailpiece connected between basket strainer and P-trap. These extensions come in various lengths to accommodate for height changes of 1/2" increments when necessary. In cases when changing size requires custom height adjustments, an inspection by professional plumber should take place to ensure safety and code compliance.
