Under-Sink Storage Ideas: A Plumbing-Aware Walkthrough

Start by Mapping the P-Trap and Pipe Runs

Before you buy a single bin or tension rod, clear everything out from under the sink. You need to see exactly where the drainpipe drops, where the P-trap sits, and how far the supply lines reach. In most cabinets, the P-trap occupies the center or slightly off-center, and it can be as low as 8 to 10 inches from the cabinet floor. Use a tape measure to record the height of the trap bottom, the width of the cabinet interior, and the depth from the front edge to the back wall. Sketch a simple top-down and side-view diagram, marking the pipe locations. This map is your reference for every storage choice you make.

Don’t forget the garbage disposal if you have one. A disposal adds bulk on one side and often shifts the drain line to the opposite side of the sink. Measure the disposal’s diameter and the clearance below it—some disposals sit only 6 inches off the floor, which rules out deep bins on that side. Also note where the hot and cold supply valves are, because you need to reach them quickly in an emergency. If you have a dishwasher, trace where its drain hose connects to the disposal or sink tailpiece; that hose usually loops up and clips under the counter, which can eat into vertical space. Knowing these details prevents you from buying stackable units that won’t fit over a hose or around a trap.

Finally, decide what actually needs to live under the sink. Common items are cleaning sprays, sponges, trash bags, dish soap, and occasionally a step stool or recycling bin. Separate them into categories: daily-use items (sponges, soap), weekly-use (cleaners, scrub brushes), and occasional-use (extra sponges, drain cleaner). This inventory tells you how much shelf or drawer area you need. For a typical 36-inch-wide sink base, you might have 15 inches of clear width on one side of the trap and 18 inches on the other, but that varies. Work with your measurements, not an idealized layout, and you’ll avoid the frustration of a rack that doesn’t clear the plumbing.

Choose Trays and Bins That Bridge the Pipes

Once your map is ready, select storage containers that can sit beside or above the plumbing, not over it. The classic move is to place a shallow metal or plastic tray on the cabinet floor on each side of the P-trap. These trays catch drips and spills, so a leak won’t soak the cabinet base. Look for trays with raised edges—half-inch is usually enough—and make sure they’re slightly narrower than the clear width on each side. For example, if the left side of the trap has 12 inches of clear floor space, choose a tray that’s 11 inches wide. This leaves a small gap for air circulation and for sliding the tray in and out.

For vertical storage, install a tension rod under the sink, perpendicular to the back wall, to hold spray bottles. This works best when the rod is placed at the front, just behind the door, so bottles hang with their nozzles pointing down and their triggers accessible. You can also use two tension rods mounted front-to-back to create a shelf for rolls of paper towels or trash bags. Just ensure the rods are firmly wedged between the cabinet sides and the bottom of the countertop, and that they don’t interfere with the door hinges. A tension rod costs a few dollars and doesn’t require drilling, which is ideal for renters.

Stackable bins with cut-out fronts are another option, but only if the P-trap is low enough. For example, a two-tier shelf with a split design—where the front half is shorter—can fit over a trap that rises to 6 inches, but not over one at 10 inches. Measure the trap’s height from the floor to the bottom of the trap curve. If that measurement is more than 7 inches, a standard under-sink shelf with adjustable legs might work, but you’ll likely need to remove the middle support bar. Some people cut a notch in a shelf’s lip to fit around the pipe, but that weakens the shelf. A safer bet is to use a wire shelf that you can bend slightly, or to skip shelving entirely and rely on hanging organizers.

Hang a Caddy on the Inside of the Door

The inside of the cabinet door is often wasted space, but you can reclaim it with an over-the-door caddy designed for under-sink use. These caddies hook over the top edge of the door and hang down, holding spray bottles, scrub brushes, and small cleaning cloths. Before you buy one, measure the door’s interior depth—most caddies are 4 to 6 inches deep—and check that the hinges don’t catch when the door opens. Also verify that the caddy’s hooks are adjustable and won’t scratch the cabinet face. A caddy with a solid back is better than an open wire one because it prevents small items from falling behind the door.

When you install the caddy, keep it away from the top edge of the door if you have a towel bar or a handle on the outside, because the caddy might interfere with the door closing flush. Also, avoid storing heavy items like full spray bottles of bleach in the caddy’s lower slots; the weight can pull the door out of alignment over time. Instead, reserve the door for light items: sponges, rubber gloves, and a small bottle of dish soap. If you have a double-door sink base, you can install a caddy on each door, but only if the doors don’t overlap when closed. Test the swing with the caddy loaded before you commit.

A door-mounted caddy works well when your under-sink floor space is limited by the P-trap. In the scenario we’re building, the left side of the trap is too narrow for a tray, but the door has 20 inches of usable height. A caddy with three tiers fits there, holding a spray bottle of all-purpose cleaner, a scrub brush, and a pack of microfiber cloths. This frees up the floor for a small step stool or a trash can. Just remember to leave the caddy’s bottom shelf clear of the hinge area, and check monthly that the hooks haven’t loosened from the door’s weight.

Use a Slide-Out Tray for the Deep Back Area

The back of the under-sink cabinet is often deep and dark, but it’s perfect for a sliding tray that you can pull forward. A simple DIY approach is to buy a plastic under-bed storage box with a low profile, cut it to fit around the pipes, and attach small furniture sliders or a drawer slide kit to the cabinet floor. However, a cleaner solution is a ready-made pull-out tray with a fixed rail that mounts to the cabinet’s side walls. These trays come in widths from 10 to 18 inches and have a weight capacity of 25 to 50 pounds. Choose one that’s at least 2 inches narrower than the clear width on the side of the trap where you plan to install it.

When installing the slide-out, position it so the tray slides out past the front edge of the cabinet by at least 6 inches. This gives you full access to the items at the back. Use a level to mark the screw holes, and drill pilot holes to prevent splitting the cabinet’s particleboard. If you have a metal or plastic P-trap that’s in the way, you can sometimes mount the tray slightly higher, but that reduces the tray’s depth. A better approach is to choose a tray with a cut-out in the back that fits around the pipe, but only if the cut-out matches your trap’s exact position. Measure twice and cut once if you’re modifying a tray.

In our worked example, the right side of the trap has 18 inches of clear width and a depth of 22 inches. A 16-inch-wide slide-out tray fits there, and you can place it on the floor because the trap is on the left, leaving the right side unobstructed. Load the tray with heavier items like extra dish soap, a box of baking soda, and a small bottle of vinegar. Because the tray slides out, you don’t have to kneel and reach into the dark back corner. This is a significant improvement over static bins, which often get pushed back and forgotten. If you’re renting, use a freestanding wire cart with wheels that fits under the sink, but make sure it’s narrow enough to clear the trap.

Work Around the Disposal with a Tension Rod Curtain

If you have a garbage disposal, the space directly below it is often unusable for storage because the disposal’s body takes up 6 to 8 inches of vertical clearance. However, you can create a hanging storage zone beside the disposal using a tension rod and a set of S-hooks. Mount a tension rod across the cabinet’s width, positioned so it sits just in front of the disposal’s bottom edge. Then hang small buckets or mesh bags from the rod using S-hooks. These can hold scrub brushes, bottle brushes, and a small plunger. This keeps items off the floor and away from the trap, and you can easily remove the bags for cleaning.

Another option is to install a shallow pull-out basket on the side of the disposal that’s opposite the trap. Many under-sink baskets are designed to fit around a disposal, with a cut-out that accommodates the unit’s shape. Measure the disposal’s width and the clearance from the cabinet wall to the side of the disposal. If there’s at least 4 inches of space, a narrow pull-out with a cut-out can slide in and out. For example, a 6-inch-wide basket with a cut-out on the right side can fit around a 5-inch-diameter disposal. This gives you a spot for extra trash bags or a roll of paper towels, which you can pull out without moving the disposal.

In our scenario, the disposal is on the right side, leaving the left side of the trap free. The tension rod curtain hangs on the left, holding a small mesh bag with sponges and a brush. The right side has a slide-out tray for heavier items, but the disposal’s bulk means you can’t use the floor directly below it. Instead, you can place a shallow bin in front of the disposal’s base, but only if the bin is shorter than the clearance from the floor to the disposal’s bottom. In a typical installation, that clearance is 7 to 9 inches, so a 6-inch-tall bin fits. This bin can hold cleaning wipes or a small trash can liner. Just be careful not to block the disposal’s reset button or the dishwasher hose connection.