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Where Does Long Beach Get Its Water?

By John Grossi

Did you ever wonder how Long Beach gets its tap water? It’s something we all take for granted, but sometimes as we mutter, shake our heads, and get down about everything that could be better in this world, it’s nice to remember how far we’ve come in some of the most truly essential necessities of life.

I never knew how it all worked, but my whole life when I’ve walked over to the faucet, refreshing healthy water fills my glass. Now that I think of it, that’s a very underrated part of our society and something we should all be thankful for.

Let’s learn more!

Q&A with Dr. Yan Zhang, Director of Water Quality and Process for the Long Beach Water Department

Q: So, where does our water come from?

A: Long Beach has two main water sources. The first is from deep under our ground. We get about 60% of our water from local groundwater wells within our city. We have about 20 to 30 wells active at any given time in the eastern and northern parts of the city. Those wells have pumps that essentially extract water from the ground, pull it up, and then push the water into two pipes that bring the water to our massive treatment facility.

The second source is, we purchase about 40% of our water from the Metropolitan Water District of Southern California (MWD). The MWD gets its water from two sources. One is from northern California as part of the California State Water Project. The other is from the Colorado River Aqueduct. Those are surface water resources unlike the groundwater we pump locally. This imported purchased water supply costs roughly twice what our local groundwater costs.

Q: What happens when the water gets to our treatment facility and what does the facility look like?

A: The facility is large and has the capability to take in roughly 62.5 million gallons a day. Normally we treat about 30-35 million gallons a day as we have a limited supply of groundwater.

Roughly 40 employees work at the facility and are split up into two divisions. The Water Treatment Division is responsible for operation of the facilities including daily treatment of the water as well as operating and maintaining the wells that bring the water to the plant. The Division operates the Groundwater Treatment Plant (GWTP) to treat the extracted groundwater through a series of processes including coagulation, sedimentation, filtration and disinfection before the water is distributed to the customers. The Water Treatment Division also coordinates with and oversees the importation of water we purchase from the MWD. This includes control over the water coming into and piped out from our plant.

The Water Quality Division’s primary job is to record the results from water quality tests to regularly make sure that the water we send out to our customers meets or exceeds what regulations define as safe drinking water standards. Our Water Quality Division performs roughly 70,000 tests a year in which they are evaluating and tracing a plethora of parameters such as organisms, bacteria, radioactivity, and any new regulatory substances that the United States Environmental Protection Agency (EPA) or State Water Board might ask us to monitor.

If anyone is interested, we publish a thorough Water Quality Report annually on our website at

Q: Once the water gets treated, how is it distributed to homes and businesses?

A: From the treatment facility, we send the water to our two reservoirs. We call the eastern half of Long Beach our “blended” zone because it receives a mix of our purchased water as well as groundwater. We send that water to our Alamitos Reservoir near the traffic circle. Much of the western half of Long Beach receives the MWD purchased water and we send that to our Johnson Reservoir right across the border from north Long Beach, in the city of Dominguez Hills.

The important difference between our reservoirs compared to reservoirs in some other places is that both of our reservoirs are situated on higher ground, which means we distribute water throughout the city solely by the use of gravity. We are not reliant on pressure pumps, which means we are not at risk of a pressure surge affecting our water supply!

Q: About how much water each day goes through this process of being pumped from a well, treated in a facility, sent to a reservoir, and then distributed all over Long Beach?

A: It varies, but on average in the winter time we send out about 40 million gallons a day to our Long Beach customers and in summertime anywhere between 50—60 million gallons a day. Before we introduced our aggressive water conservation campaign a few years ago, it could be as high as above 70 million gallons a day during the summer. We really appreciate how much Long Beach has committed to conservation and hope they know the impact it is making. The more we can conserve the more we are prepared to handle unexpected shortages from Mother Nature as well as keeping our water bills relatively inexpensive

Q: How would Long Beach handle a water crisis?

A: One of the main reasons we source water from two separate places (Long Beach groundwater and northern California/Colorado River surface water) is because the two sources serve to back each other up. In a year where the water supply is short, we already have relationships and capabilities in place that allow us to draw from either or both of these sources. If we need more water from Northern California or the Colorado River, we get priority rights to purchase as a MWD member agency. The downside is that it costs more to purchase imported water, which is why conservation is so important. The goal is to save money while remaining a member of the MWD so that we have a direct relationship to Northern California and the Colorado River.

We also take pride in the fact that we currently have 20-30 active wells in Long Beach. We are working on a comprehensive well program to build more wells and maintain our existing wells to ensure our capacity to pump groundwater. This allows us the flexibility to seamlessly fix and maintain the wells as we can rotate between them, allowing us to continue to maximize our local pumping.

Lastly, our reservoirs are large enough to meet our normal usage demand, and then some. State law mandates a municipality to have at least 4 hours of reserve water at all times. However, our reservoirs can hold enough water for 3-4 days giving us a great cushion if ever we would need it during an emergency situation.

Q: Where does the groundwater in Long Beach come from?

A: The groundwater we extract is from the Central Groundwater Basin, which is in the San Gabriel Valley Watershed. The groundwater basin gets its water from two sources. One is the rain and snowmelt flowing through washes and creeks into the San Gabriel River and Whittier Narrows before percolating into the underground aquifer. The second source is the Water Replenishment District’s (WRD) groundwater recharge programs whereby WRD continually adds or replenishes recycled water and Advanced Treated recycled water to the underground aquifer to maintain the availability of local groundwater supplies.

Q: Anything else you would like to say to the water customers in Long Beach?

A: Some key messages we want to send is that we do have sufficient supply from both surface and groundwater and that our drinking water is treated and tested to ensure that it is clean, safe, and tastes great! We have programs in place to make sure our residents have sufficient supply at all times and our sources are very reliable. But at the same time we want to keep the message going that water is a very precious resource so make sure our residents keep conserving and try to keep our water demands low. Simple things can make a big difference. Turn off the water while you brush your teeth or wash your car or do dishes. Every act of conservation helps to keep our water affordable and accessible for all!



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