Short answer: yes, a domed top usually helps—but it doesn’t make a trash can completely waterproof or self-draining. The dome acts like a small roof. Rain runs off the curved surface instead of pooling on a flat lid or pouring straight into an open top. That means less water sits on the lid, and less rain gets into the bin, so the bag stays drier and the can is lighter and easier for city crews to service.
But “less” is not “none.” If the dome has a deep rim, a damaged hinge, or an opening around a push flap or side door, rain can still get in. Water can also collect around the base, in foot wells, or inside the bin if drainage holes are clogged. In busy urban areas, litter blocking gaps is a real issue. And a domed top doesn’t stop wet waste or humidity inside the bin from creating moisture.
So domed urban trash cans generally do reduce rainwater buildup, especially compared with flat-lidded or open bins. The design works best when the dome overhangs the opening, drainage holes stay clear, the lid fits well, and maintenance is regular. It’s a practical rain-management feature, but it’s not a guarantee—expect a drier bin, not a perfectly dry one in a downpour.