Those Black Streaks on Your Roof Aren't Dirt — What They Are and How to Remove Them Safely

Under Pressure Washing 518 Team

Published on: 22/09/2026

Those dark stains running down your shingles are almost always algae — and they're more common in the Capital Region than most homeowners realize. This guide explains what's causing them, why they shouldn't be ignored, and what safe, effective roof cleaning actually looks like.