If a drain pipe runs through your under sink cabinet, standard shelving doesn't fit — the U-shaped P-trap sits low and dead center, and the shut-off valves stick out behind it. You don't need to move plumbing. You need to organize around it, and there's a specific order that makes that easy.
Find the lowest point of the trap
Get a tape measure and record the height from the cabinet floor to the bottom of the trap's curve, plus how far the pipe sits from the back wall. Most cabinets have 8 to 12 inches of clear floor on each side of that pipe. Those two side zones are where your storage goes.
Split the cabinet into three zones
Left of the pipe, right of the pipe, and the air above it. The two side zones take tiered storage. The space above the trap only works for shallow, lightweight items — never park a heavy basket on top of plumbing, and leave the trap accessible so a leak can be seen and fixed. How much those side zones hold comes down to the clear height under the pipe. Under 12.2 in, no tiered unit fits at all. Between 12.2 and 15 in, only a door-back hanger works. From 19.1 in up, a 2-tier organizer starts to clear. The clearance table runs each measurement against what fits.
Use an organizer with adjustable legs
This is the part most people get wrong: they buy a fixed rack, discover the leg lands on the pipe, and return it. The SinkFlex 2-Tier Pull-Out Under Sink Organizer ($33 for a 2-pack) exists for pipe cabinets — each unit's shelf height adjusts, so you can set one low on the wide side and one high to clear the trap, then slide the baskets out to reach the back without leaning over the plumbing.
Store tall things upright, flat things vertical
Spray bottles and refill jugs go on the open cabinet floor. Pot lids and baking sheets should stand on edge rather than stack — that's what the Adjustable Pot & Lid Organizer ($30) does, and its height adjusts around pipes too.
Leave the valves alone
Keep a few inches of clearance around the shut-off valves. If a plumber can't reach them, or you can't turn them in a hurry, the setup is a problem no matter how tidy it looks.
One more check while the cabinet is empty: run your hand along the cabinet floor under the trap. A slow leak that only drips while the sink is running leaves a musty smell long before it leaves a puddle — the 24-hour paper towel test tells you whether that damp patch is a spill or a leak, and the two need different answers. The same idea applies when a disposal is in the way — what fits around a garbage disposal starts from the clearance it leaves you.
Working with a pipe-heavy cabinet? Start with the SinkFlex Pull-Out Organizer, or see the full under sink guide.
Pipe cleared? Width is the next constraint. If the whole cabinet is around 15 in wide, even a rack that clears the trap can be too wide to land beside it — what actually fits a small under sink cabinet covers the pieces that still work at that width.