Under-sink storage works best when it is organized around plumbing, shutoff valves, and possible leaks rather than packed wall to wall. Keep service access clear and separate products that should never be mixed.
Empty the cabinet and check for moisture first
Remove everything, clean the cabinet floor, and look for staining, swelling, or drips around the trap and connections. Do not hide a leak behind bins; fix moisture before putting supplies back.
Keep plumbing and shutoffs accessible
Leave enough room to see and reach shutoff valves and the trap without unloading the entire cabinet. Low bins or narrow drawers can use the sides while keeping the center accessible.
Separate incompatible and hazardous products
Do not store bleach beside acids or ammonia where spills could mix. Keep chemicals in original labeled containers, closed securely and out of reach of children and pets.
Use small removable categories
Group dishwasher supplies, bags, cloths, or spare parts in bins that lift out as a unit. That makes leak cleanup easier, improves visibility, and prevents forgotten items from accumulating behind plumbing.