Runoff is rain that falls onto hardscape such as the asphalt and concrete of driveways, walkways, and streets. These impervious surfaces in our urban environment prevent stormwater from naturally soaking into the ground.

Following 3 years of GreenTown advocacy, in November 2018 the Los Altos City Council voted to adopt eco-friendly solutions to capture dirty street runoff. The Shoulder Paving Policy, which applies to all new residential construction and major remodels, embraces permeable materials in the City Right of Way. Organic materials allow rain to sink into the ground, where toxins are captured and decompose. These “green streets” keep polluted water out of our waterways. The abundance of natural frontage in Los Altos, streets without curbs and gutters, offer tremendous opportunity to maximize stormwater capture.

Believe it or not, the single largest source of pollution in the San Francisco Bay is stormwater runoff. Runoff flows through the system of curbs and gutters to storm drains that empty directly into our watershed. Along the way, beautiful rain transforms into a pollutant.

Stormwater runoff picks up oil, grease and metals from cars, chemicals that leech from asphalt, fertilizer, herbicides and insecticides from our landscape, and pet waste laden with bacteria and viruses. These pollutants pose health risks to humans, wildlife, and plants.

Minimize Hardscape. Maximize Greenscape.

Be a part of the solution to stormwater pollution! Capturing rain where it falls helps to keep our waterways clean and healthy. Rain water is easily captured in rain gardens, vegetated swales, catch basins, dry creeks and other greenscapes. The water is purified as it gradually percolates through the soil and recharges our aquifers.

To learn more watch the videos in the resources section: “Capture Rain Where It Falls”

The "Permeable Surfaces Handbook" is a comprehensive, innovative guide designed to educate readers on easy installation of permeable surfaces, aligning with the Los Altos city code for permeable surfaces for sidewalks, walkways, patios, driveways and/or uncovered parking lots. It provides practical advice on installation and maintenance, aiming to help both DIY enthusiasts and professionals implement these eco-friendly solutions.

The handbook was developed by high school student Aanya Dhruv. She worked with city engineers and iterated the guide to get it up to Los Altos housing codes. Aanya leads the ejgrassroots.org initiative that is focused on environmental justice and leveraging science to solve environmental issues.