Why do black streaks come back after I've already cleaned them?

Usually because the source -- mildew and grime buildup on the roof -- wasn't addressed at the same time as the siding. Cleaning the streak without cleaning and inspecting the roof often means the same streak reappears within weeks.

Can I use a regular degreaser to remove RV black streaks?

It can work but risks dulling or damaging the siding's clear coat with repeated use, especially on fiberglass. A purpose-built RV black streak remover is formulated to avoid that risk.

How much should black streak removal cost as an add-on service?

Typically $75-$200+ depending on RV length and streak severity, priced as its own line item separate from a standard exterior wash because of the extra dwell time and agitation required.

Does a UV protectant actually slow down future black streaking?

Yes, applying a UV-protectant sealant or wax after cleaning makes the surface harder for mildew and residue to bond to, which meaningfully slows how quickly streaks return compared to leaving the siding unprotected.

Is black streak removal safe for all RV siding materials?

Most purpose-built black streak removers are formulated to be safe on fiberglass and painted siding when used as directed, but always spot-test on a small area first, and use extra caution on decals or graphics, which can be more sensitive than the surrounding siding.

How to Remove Black Streaks from RV Siding

What actually causes black streaks running down RV siding, the products and process that remove them safely, and how to prevent them from coming right back.