Water

A precious, contested resource.

Watershed Health Index

The map below is about the ability of our watersheds to support ecosystems and habitats. While some drinking water systems in Southern California rely on their own watersheds, many do not.

Water Icon

The map above shows a clear relationship between urbanization and poor water quality (light blue areas). Impermeable surfaces where water can’t penetrate are part of the problem—creating lack of groundwater recharge and water filtration as well as increased flood risk.

Click on the map to find out where your neighborhood stands. Explore solutions like de-paving, daylighting, permeable surface materials, and expanding urban greenspace. Collectively, we can turn more of this map dark blue!

Where does Southern California water come from?

Water reflects everything about us. It's part of us...approximately 98% part! The water cycle is the ultimate closed loop system. But with so many compromises along the way (toxins, melting, evaporation, innundation, saline contamination), how we adapt to our changing water system is increasingly important.

Anatomy of Water Sources in Southern California

Reducing our Debt

Overreliance on water resources from outside of Southern California creates a situation of “ecological debt.” Essentially, this means we are living beyond our means—a problem we have solved by taking water from other regions. Water challenges aren’t exclusive to Southern California. Increasingly, So Cal water sources from a variety of locations are also changing. But cities like Los Angeles have goals to reach 100% local water through water capture, water recycling, and water conservation. Go LA!

The Color of Water

Did you know that there are many different kinds of water? Some colors (green, blue, grey, black, and purple, below) are how we designate water types. Other color terms (red, orange, yellow, even pea soup!) are reflective of off-color water due to algal blooms or a high presence of minerals like iron.

Flip the color boxes below to find out how some of the colors of water are connected and others are connected to climate change and out-of-whack ecosystems.

Green Water

Green water is water for plants! It's in the soil where we humans and animals can't get it. That's a good thing! Imagine plant roots as special kinds of straws that the plants use to suck water and soil nutrients into their stems and leaves. Think of the term moisture. That's what green water is.

Blue Water

Blue water is water that is accessible and drinkable by you, your dog, a coyote, bugs, butterflies, and everyone else. It's on the earth's surface and can be pooled in ponds, flow along in streams and rivers, or be contained in reservoirs for human consumption. Blue water is life giving and precious!

Purple Water

Welcome to the wonderful land of water recycling! Purple pipe water is used, contaminated water that has been treated and purified and gets back out there for consumption. This system mimics what nature does, because all water is recycled through the water cycle. Sometimes people are a bit suspicious of purple pipe water, and so it tends to be used for irrigation instead of coming into people's homes. But it's an excellent and also underutilized water source that can make us less reliant on outside water imports and unneeded energy expenditures!

Pea Soup!

Pea Soup usually means an algal bloom--dangerous for human and animal health. Pea soup can be lots of different colors, odors, and textures...but it general means that the water ecosystem is way off. Increased heat is throwing ecosystems out of wack and an increase in algal blooms is a signal of some serious issues. 

Grey Water

Grey water is an underutilized water resource. Grey water can come from rainfall on your roof, your bathtub or laundry, and then can be utilized to water your garden. Grey water morphs right into green water. Given how much water our homes and businesses we use daily and how much water we use for landscaping, grey water is a double win. Using grey water also reduces energy consumption. Plants naturally filter out the impurities in grey water, which then goes back into the water cycle.

Black Water

Black water has to do with, you guessed it, poop. It's what gets flushed from your toilet down through the sewer system.  But guess what? Water treatment plants can turn black water into various other water types.

Orange/Red Water

Orange or reddish water may mean the presence of minerals such as iron. Did you know that a river turned orange in Alaska recently? Because permafrost is melting, the amount of iron in the water increased dramatically! With climate change and older infrastructure, water that changes color is increasingly common.

Yellow Water

We know what you're thinking...

And no it's not about pee. There is no simple answer to this one. Like its orange/red cousins, yellow can also mean iron. Or Manganese. Or chlorine. Or that the water systems has been recently flushed. It can mean there is decaying vegetation...so many causes of yellow water. It's usually safe to drink but try a water filter if you're uncomfortable!

Get to know the Metropolitan Water District

Behind every faucet in SoCal: A giant you’ve never met.

By Celia Malone '24

 

The Metropolitan Water District of Southern California (MWD) is the largest supplier of treated water in the United States, delivering water to 26 member public agencies that serve nearly 19 million people across six counties.

The MWD also controls over 180,000 acres of land, including critical infrastructure along the Colorado River and in the Sierra Nevada foothills. It imports water from both the Colorado River and the State Water Project, providing up to 2.1 billion gallons per day—enough to fill the Rose Bowl 26 times.

MWD’s quiet reach extends not just through pipelines, but across policies that shape agriculture, urban development, and climate resilience in the arid West.

Adelanto: Water Justice in the High Desert

More of our favorite water projects…

Owl Swimming (1)