Rainy-Season Tannin Bleed and the Fence Water Test

Brown streaks show up under a lot of San Diego fences after the first rains. A two-minute water test tells you whether your fence is protected and what to do before the next storm.

Why the Rainy Season Brings Brown Streaks

Redwood and cedar hold natural water-soluble tannins. Through the dry months a bare or worn fence barely gets wet, so nothing happens. When the first real rains arrive, water soaks the boards, pulls those tannins out and drips them onto the patio, driveway, block wall or stucco below. In San Diego most of our rain falls in the cooler months, so this is when homeowners usually notice it. For the basics on new wood, see our guide to tannin bleed from a new redwood or cedar fence.

The Water Test: Is Your Fence Protected?

You can check your fence in two minutes with a cup or spray bottle of water:

Sprinkle water on a few boards. Test a sunny side, a shady side and a bottom board near the ground or sprinklers.
Water beads up: the finish is still keeping water out.
Water soaks in and the wood darkens within a minute or so: that area is open to water and is likely to bleed or gray.
Look below the fence for old brown or orange streaks. They show where water has already been running off.

The same test tells you when it is time to restain. Our guide on how often to restain a fence Coastal Salt-Air Fence Care covers the other signs.

What to Do Before the Next Storm

Turn sprinklers away from the fence.
Pull soil, mulch and leaves away from the bottom boards.
If the water test fails, plan to stain during a dry stretch. Stain needs dry wood, so we schedule around the forecast and check the boards first.
Building a new fence? Pre-staining the boards before they go up protects all sides from day one.

If It Is Already Bleeding

Rinse fresh streaks off concrete or stucco quickly. Older stains often lighten with an oxalic-acid wood brightener or a cleaner made for tannin stains. Test a hidden spot first and rinse well, especially near plants and colored concrete. Once the season dries out, cleaning and staining the fence keeps it from happening again. If the wood has darkened or grayed, our fence restoration service cleans and brightens it before staining.

Pricing and Estimates

Fence staining runs $7–$10 per linear foot per side, and pre-staining a new fence runs $16–$22 per linear foot. We give free on-site estimates across San Diego County. Call 858-754-9842 or request a free estimate.

Frequently Asked Questions

How do I do the water test on my fence?+

Splash or sprinkle a little water on a few boards, including a sunny side, a shady side and a bottom board. If it beads up, the finish is still protecting the wood. If it soaks in and darkens the wood within a minute or so, that area is bare enough to absorb water and bleed tannins.

Why do the brown streaks show up after the first rain?+

Rain is often the first real soaking a bare redwood or cedar fence gets. The water carries the wood's natural tannins out and leaves brown or reddish marks on concrete, pavers and stucco as it dries.

Can you stain a fence in the rainy season?+

Yes, during dry stretches. Wood has to be dry before stain goes on, so we schedule around rain and check the boards before we start.

Will staining stop tannin bleed?+

A penetrating oil-based stain helps keep water out of the wood, which is what moves the tannins. Existing stains on concrete still need to be cleaned separately.

Tannin Bleed From a New Fence How Often to Re-Stain Wood Fence Staining Pre-Staining Fence Restoration Contact Us

Fence Failing the Water Test?

Call 858-754-9842 or request a free estimate.

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