How to Prepare Your Culverts and Drainage Before Winter

The short version

• Before the first storms, clear every culvert inlet and outlet of the summer's needles, leaves, branches, and silt. A blocked outlet is as bad as a blocked inlet.
• Clean the roadside and yard ditches that feed the culverts, or the water never reaches the pipe.
• Point gutters and downspouts away from the foundation, and watch for soil eroding around a culvert or a sagging road edge.
• Do it on a dry day, wear gloves, and never work in flowing storm water.
• Culverts on your own property and driveway are yours. County-maintained roads are the county's; report a blocked one to Santa Cruz County Public Works at (831) 477-3999. Private shared roads usually fall to the owners.

The first real storm finds every culvert you forgot about. One clogs, the water backs up, and by morning your driveway is running like a creek or a piece of your road has slid downhill. The culprit is almost always the same: a blocked culvert or overwhelmed drainage. Culverts are the pipes that carry water under driveways and roads, and in a redwood canyon they clog fast with needles, leaves, and silt over a dry summer.

Clearing them before the rains is some of the highest-value storm prep you can do, and it's mostly a shovel-and-gloves job. Here's how to think about it, and who's responsible for what.

Why culverts matter so much here

Mountain storms drop a lot of water fast, and that water has to go somewhere. When a culvert is blocked, the water backs up, jumps the road or driveway, and carves a new path, often straight through the dirt holding your road up.

A single plugged culvert can wash out a driveway, flood a garage, or cut off access. Keeping them clear is the difference between water passing under your road and water taking your road with it.

What to do before the rains

• Find your culverts and drains. Walk your property and driveway and locate every culvert inlet and outlet, plus roadside ditches and any drains around the house. They're easy to forget until they fail.
• Clear the inlets and outlets. Remove the summer's needles, leaves, branches, and built-up silt from both ends so water can flow through. A blocked outlet is as bad as a blocked inlet.
• Clean the ditches that feed them. Roadside and yard ditches that carry water to the culvert need to be clear too, or the water never reaches the pipe.
• Check the roof-to-ground path. Make sure gutters and downspouts carry water away from the house and toward a drain, not against the foundation.
• Watch for undermining. If you see soil eroding around a culvert or the road edge sagging, that's a warning sign to address before a storm makes it worse.

Do this on a dry day, wear gloves, and never work in flowing storm water. If a culvert is collapsed or badly undermined, that's a job for a professional or, on a county road, for the county.

Who's responsible for what

This is where people get tripped up. In general, culverts and drainage on your own property and private driveway are yours to maintain. Culverts under county-maintained roads are the county's responsibility, and you can report a blocked or failing one to Santa Cruz County Public Works, whose 24-hour road dispatch is (831) 477-3999.

Many roads up here are private, though, shared by the neighbors on them, and on those the maintenance, including drainage, usually falls to the property owners. If you're not sure whether your road is county-maintained, the county can tell you.

During and after storms

If you can safely see that a culvert is starting to back up during a storm, clearing the debris at the inlet can prevent a washout, but only if you can do it without stepping into moving water or a flooded ditch.

After a big storm, check your culverts again; they often clog mid-storm and stay blocked. For the bigger post-storm walk-through, see what to do after a major storm.

Frequently asked questions

What is a culvert and why does it clog?

A culvert is a pipe that carries water under a driveway or road. In the redwoods they fill with needles, leaves, and silt over the dry season, and a blocked culvert backs water up and causes washouts and flooding.

When should I clear my culverts?

Before the first major storms, ideally in early fall, and again after big storms, since they often clog mid-storm. Do it on a dry day and never work in flowing water.

Who's responsible for the culvert on my road?

Culverts on your own property and private driveway are yours. County-maintained roads are the county's (report issues to Public Works at (831) 477-3999). Private shared roads are usually the owners' responsibility. Confirm with the county if unsure.

Last reviewed July 20, 2026. Details here follow official sources from Santa Cruz County Public Works.

Storm prep, not storm response. Report blocked culverts on county roads to Santa Cruz County Public Works at (831) 477-3999. For live conditions, see Mountain Status, and for the rest of the season's checklist, the Residents guide pulls utilities, permits, and county contacts into one place. In an emergency, call 911.