What you're probably noticing
Maybe it's the smell in the back bedroom that wasn't there last summer. Maybe it's a faint discoloration creeping along the baseboard in the unit closest to the canal, or a windowsill that stays damp long after the marine layer burns off. If you live near the Venice canals, on one of the walk streets close to the beach, or in one of the older bungalows east of Lincoln, you've probably felt a version of this. The ground here sits close to sea level, the water table is high, and a lot of houses were never built with that fully in mind.
Why Venice houses are especially exposed
Much of Venice's housing stock dates from the 1920s through the 1950s, with crawl spaces, low foundations, and plumbing that was never designed for a hundred years of settling sandy soil. Add to that the canals, the marina, and a water table that rises and falls with the tide, and you get a lot of homes sitting closer to moisture than their original builders assumed. Newer construction on infill lots sometimes fares better, but even those can trap humidity if they were built airtight without enough ventilation in the crawl space or attic.
The marine layer that rolls in most mornings, especially from late spring through early fall, keeps humidity high for hours at a time. It doesn't rain much, but the air stays damp, and that dampness gets into wood framing, insulation, and drywall slowly, over years, rather than all at once in a single storm.
More on this from Living Beside Standing Water And Keeping The House Dry.
What standing water near your home actually does
If your property backs onto a canal, sits near a low spot that collects runoff, or has a yard that never quite drains after a winter storm, that water is doing something to your foundation whether you see it or not. It seeps laterally through soil into crawl spaces. It wicks up through concrete slabs that weren't sealed well to begin with. It raises the humidity in the air right around your house, which matters more than people think, because mold doesn't need a flood. It just needs consistent moisture and something organic to feed on, which describes most building materials.
Venice's rainy season is short, usually concentrated in the winter months, but when it comes, streets and low yards can hold water for days. If your gutters dump close to the foundation, or your yard grades toward the house instead of away from it, that's worth fixing before the next winter, not after.
What you can check yourself
Walk your crawl space with a flashlight if you can get under there safely. Look for damp soil, water stains on joists, or a musty smell that's stronger than the rest of the house. Check under sinks, around water heaters, and along exterior walls that face the canal or a low part of the yard. Look at your gutters and downspouts after the next rain and see where the water actually goes. A lot of drainage problems in this neighborhood come down to a downspout dumping six inches from the foundation instead of six feet.
Inside, keep an eye on anything that stays damp without an obvious reason: a closet that never seems to dry out, a window that fogs on the inside even when it's not that cold, paint that bubbles low on a wall. None of these are emergencies by themselves, but they're the kind of thing worth writing down and watching over a few weeks.
When it stops being a homeowner job
If you can see mold, you can usually clean a small patch yourself with the right precautions. But if you're smelling it more than seeing it, or if the same spot keeps coming back after you've cleaned it, that's a sign the moisture source hasn't been dealt with, and it's worth having someone look at what's happening behind the wall or under the floor, not just at the surface. This matters more in older Venice homes because a lot of the framing and subflooring is original, and once moisture gets into wood that's been there since the 1930s, it doesn't dry out the way newer lumber does.
A proper mold inspection isn't about spraying something and calling it done. It's about tracing where the moisture is actually coming from, whether that's the canal side of your lot, a cracked slab, or a bathroom fan that's been venting into the attic instead of outside. If you've checked the obvious things yourself and the problem keeps returning, that tracing work is where a homeowner's job usually ends and a professional's begins.