Have you ever wondered what that giant tank on the hill was? You are looking at a water tank reservoir storing water for your community. Water reservoirs are a means to store both drinking (potable) and non-drinking water (non-potable). Reservoirs can be in the form of a lake or tank. Beneath the ground you can also find natural underground reservoirs where water is stored until it can be pumped, treated (cleaned) and delivered to homes.

Paradise Meadows

Eastern Municipal Water District’s Paradise Meadows Reservoir sits high above the hills of the Audie Murphy Ranch development.

Potable water tank reservoirs  store water that has already been treated and is waiting to be delivered to homes and businesses. In California, due to the mountainous terrain, reservoirs are usually placed in higher elevations. The reason for placing the tanks higher than the homes and businesses is because pressure is needed to push water through the pipes. The water that leaves the tanks travels by gravity flow. The water pushes through the distribution system (pipes) and the pressure depends on the elevation and distance of the reservoir that provides water to a home. A water pressure regulator is a device that can be installed to regulate pressure to ensure the correct amount of pressure is present.

Orangecrest Reservoir

The water inside the Orangecrest Reservoir, in Riverside, is managed by Western Municipal Water District.

Reservoir tanks ensure that the correct amount of water is treated and ready to be distributed to the areas they provide water to. When people turn on the tap to take a drink of water, enjoy a shower or wash their hands, water travels directly from a nearby reservoir,  through pipes and into homes. The process happens so efficiently that most people never think twice about where their water comes from or how it gets to them. Besides residential, commercial and industrial water demands, reservoirs also store surplus water held in reserve in case of high fire flow water demand.  This ensures adequate water is supplied to fire hydrants when firefighting is needed.

“There are several benefits of a tank reservoir versus an open reservoir,” shares Liza Muñoz, Inland Empire Utilities Agency Senior Engineer.  “Tanks allow you to store a large amount of water in a smaller footprint than in an open reservoir. They also avoid water evaporation, which can reduce supply. Tanks are designed to supply water at the appropriate system pressures needed to deliver the water.”

930 West Reservoir in Chino Hills

930 West Reservoir in Chino Hills stores recycled water for agriculture, irrigation, industrial cooling processes, and groundwater replenishment.

Inland Empire Utilities Agency (IEUA) has five above ground tank reservoirs to store treated recycled water for non-potable (not for drinking) water. The recycled water is stored in the reservoirs and then distributed to IEUA’s member agencies for non-potable use in agriculture, irrigation, industrial cooling processes, and groundwater replenishment. The water stored in these tanks comes from IEUA’s regional water recycling plants and are governed by California Title 22. Stringent water quality testing is conducted so that recycled water quality meets/exceeds regulatory standards in order to be reused for non-drinking water purposes.

Both drinking water and treated recycled water can benefit from being stored in tank reservoirs. Next time to you look up at a hill and see a tank reservoir, be sure to remember that inside that large tank there are possibly millions of gallons of water inside waiting to travel through your city.

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An inside view of the San Bernardino Perris Hill Reservoir after being drained.


Water is a finite resource. We cannot make more of it. The same water on earth today is the same water that was here during the times that dinosaurs roamed.

Southern California’s dry climate with little rainfall requires the need for a sustainable and secure supply for water. With record breaking dry periods, such as the most-recent drought that took place over the course of five years from 2012 to 2017, water agencies throughout California are looking for solutions for maintaining a sustainable drinking water supply. It is more important than ever to become less dependent on  imported water and reduce costly sources of water to support the region’s demand. Dry years forced water agencies to look for innovative and progressive avenues that create local viable supplies of water.


Advancements in technology, water treatment facilities and innovative thinking have created wastewater recycling and groundwater recharge. This approach to water supply management gives Southern California agencies a feasible option to meet the needs of its commercial and residential customers while preserving groundwater basin levels.

What exactly does wastewater recycling mean? It is a highly sophisticated process that the Environmental Protection Agency describes as “reusing treated (cleaned) wastewater for beneficial purposes such, as agricultural and landscape irrigation, industrial processes, toilet flushing, and replenishing a groundwater basin (referred to as groundwater recharge).” California’s Department of Water Resources describes groundwater recharge as “the augmentation of groundwater, by natural or artificial means, with surface water or recycled water.”

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This wastewater treatment and reuse process is currently being used for both non-potable (not consumable) and potable (consumable) via recharge across the region. Orange County Water District (OCWD) has led the way in developing and implementing a water purification system for indirect potable reuse. Its Groundwater Replenishment System (GWRS) is considered the world’s largest of its kind and serves as a global model for water reuse.

“Wastewater is a resource. That is why OCWD has made a significant investment in implementing and expanding the Groundwater Replenishment System . In fact, by 2023 the GWRS will produce 130 million gallons of water a day. The GWRS creates local water reliability and helps OCWD diversify its water portfolio. These types of projects have tremendous potential throughout California, and beyond. As water managers, we must look at all available options in our region to create long-term water reliability and water reuse should be considered,” shared OCWD General Manager Mike Markus.


The GWRS takes highly treated wastewater that would have previously been discharged into the Pacific Ocean and purifies it using a three-step advanced treatment process consisting of micro-filtration, reverse osmosis and ultraviolet light with hydrogen peroxide.  In order to simultaneously maintain the groundwater basins integrity that was no longer being sustained by natural recharge, and to satisfy the demands of their ever-growing population, Orange County Water District will  replenish the supply with purchased imported sources as needed. Although the GWRS creates more local water reliability, Orange County Water District is still reliant on other water sources. The GWRS does reduce dependence on other water sources by 30 percent.

GWRS enabled the water district to reduce the need to purchase imported supplies and instead allowed them to recharge their basin with their wastewater that had been extensively treated. Their process is often described as a state-of-the-art production that creates a high quality, local indirect potable supply which is beneficial to all its consumers. Different types of this supply model, albeit smaller in production, are imitated throughout the region.


Although treatment plants and techniques have become increasingly modified, using recycled wastewater to meet demands is not entirely new. In fact,  according to the Department of Water Resources, it is a technique that has been used for over a century.  During the late 1800s farmers began using wastewater to grow crops and others started using it for landscape irrigation. Investing in infrastructure for these operating systems usually requires a larger upfront cost but provides multifaceted benefits that often offset and surpass the cost. The Department of Water Resources list the following benefits for recycled water:Restores wetlands and marshes;

• Forestalls a water shortage by conserving fresh water;

• Provides additional reliable local sources of water, nutrients and organic matter for soil conditioning;

• Provides drought protection;

• Improves the economic efficiency of investments in pollution control and irrigation projects, particularly near urban areas;

• Improves social benefits by creating more jobs and improving human and environmental health protection.

Water districts understand the public health concerns regarding the use of recycled water, which is recharged in the groundwater basin and later used for potable water. They battle the misperceptions by ensuring quality tests meet and exceed mandatory state and federal regulations for drinking water. With increasing demands and an unpredictable future in California’s climate, building infrastructure for recycling wastewater for groundwater recharge is an option that is becoming increasingly popular to increase local control of water of resources.

BPA has made headlines repeatedly over the years and prompted a public outcry for more information over the topic. Many people have called for its ban and expressed concerns over the presence of BPA in everyday household items. The overwhelming presence of BPA in food and drink containers may be negatively impacting a wide range of bodily functions independent of age, race, or gender. The long term consequences of involuntary and long-term ingestion of the chemical raises the question of how to avoid it.

Bottled water BPA

What is exactly is BPA? The Mayo Clinic defines BPA, short for bisphenol A., as an industrial chemical that has been used to make certain plastics and resins since the 1960’s. The Clinic further explains that “BPA is found in polycarbonate plastics and epoxy resins. Polycarbonate plastics are often used in containers that store food and beverages, such as water bottles.” Essentially, BPA is a chemical that has been used in plastic productions for nearly 70 years and is universal among plastic-based container goods. BPA becomes problematic when used in everyday items such as water bottles and Tupperware due to the susceptibility of the chemical leaching into the contained product, i.e. food or beverages. This in turn leads to the chemical unknowingly being ingested and causing short and long term ailments. The Mayo Clinic reinforces that notion and states, “Some research has shown that BPA can seep into food or beverages from containers that are made with BPA. Exposure to BPA is a concern because of possible health effects of BPA on the brain, behavior and prostate gland of fetuses, infants and children. Additional research suggests a possible link between BPA and increased blood pressure.”


Your So Cal Tap Water previously had the opportunity to interview Brenda Meyer, an engineer and water scientist from Western Municipal Water District, about the regulations that tap water is mandated to follow. We learned that besides BPA contamination concerns, bottled water also faces looser regulations in the filtering process compared to tap water. This is not to say that bottled water is unsafe to consume, but does reinforce the notion that tap water faces strict regulations by the Environmental Protection Agency (EPA) and is monitored to maintain its quality. Bottled water is regulated by the Food and Drug Administration (FDA) and is subject to weekly test for bacteriological contamination in California; while regular bottled water testing is suggested, it is not always enforced and often goes loosely regulated. Municipal water districts are subject to more rigorous quality tests on a frequent basis and take pride upholding the integrity of the resource.

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Time Magazine online shares a recent study, conducted by Orb Media, on the contamination of 9 of the 11 bottled water tested for Microplastic contamination testing positive. The findings were nearly universal discovering Microplastics in 90% of the samples tested. Compared to bottled water from around the globe, those tested from U.S. sources ranked higher for contamination. Furthermore, the environmental impacts of the bottled water are also a concern if not addressed.

We know that tap water is BPA free, regulated, and wallet-friendly to consume, but still the United States is experiencing an increase in sales of bottled water. According to data released by Beverage Marketing Inc., “Theamount of bottled water sold rose 7.9 percent in 2015. That’s on top of a 7 percent increase in 2014. Looking over a long term time span, from 2000 to 2015, bottled water consumption more than doubled, from 16.7 gallons a person to 36.4 gallons.”

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Americans are consistently purchasing and consuming more bottled water than ever before and potentially exposing themselves to hazardous chemicals in the process. Besides the convenience of purchasing bottled water, packaging is valued for its aesthetic components and media ‘worthiness.’ National Geographic speaks to the anti-bottled-water campaigns “which have been concentrated on the nation’s college campuses and focus on the environmentalimpact of bottled water as a packaged product, compared to simply refilling a reusable water bottle,” but concludes that the movement needs more engagement from the public.

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Staying BPA free is possible and there are many simple steps you can take to avoid it. Using a reusable bottle and filling it with tap water helps avoid environmental and health consequences that plastics containing BPA can produce. Choosing the right refillable bottle identified with ‘BPA free’ stickers or signage are also instrumental to avoiding the chemical in your household items. Whatever the case, be reassured that filling it with tap water is safe and monitored as well as economically friendly for any home!

To read our  interview with Brenda click here.

There is no question about it, according to the CDC, this year has been one of the worst recent years for the flu on record. If you have ever had the flu, you know that it can affect your entire system and halt your plans for several days, if not longer. One moment you are feeling well and the next the flu symptoms wreak havoc on your health. Fevers, aches and body chills, among many other unpleasant symptoms, stop your ability to function in your day-to-day routine. The symptoms of the flu hit children and elderly people the hardest. There are many precautions you can take to deter the flu, such as getting a flu shot at your local pharmacy, staying away from people who have the flu and washing your hands often. There are also holistic home remedies that claim to help avoid the illness as well. However, there is no way to guarantee that you won’t contract the flu. Germs spread quickly and varying strains of the flu can be stronger than others.

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In addition to taking necessary precautions, maintaining a healthy lifestyle is a key part of preventing the flu. A large part of healthy living is nourishing your body and drinking adequate amounts of water to enhance your immune system. Since more than half our bodies are composed of water, drinking the recommended amount may help you, and loved ones, end the flu season unscathed.

Most people know you are supposed to drink plenty of fluids when they are sick with the flu, but did you know that drinking water, including tap water, and staying hydrated year-long can actually help prevent it altogether? Water is essential for our bodies to operate and giving it the right amount strengthens its functions. Dr. David Lewis explains that “the first line of defense is the mucous membrane in the nose,” and, “[it] acts like a sticky flypaper to trap things like dust, dirt and bacteria and prevent them getting to the lungs. If you are dehydrated, the mucous membrane will dry out. When this happens, it is half as effective.” To keep your first line of defense in optimal, flu-fighting shape, it is imperative to drink enough water to fuel it so that it can block undesirable bacteria and viruses through this canal.

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Everyday Health affirms that drinking the recommended amount of water is beneficial to your health and one recent study “found staying hydrated may boost a particular immune response to enable your body to better fight the viruses.” This allows your body to avoid contracting the flu and fight off any unwanted symptoms but needs to be fortified with proper hydration and health. Boosting your immune system allows your body to ward off the flu before it becomes potentially  problematic, as it often does with people that have weak immune systems.

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Because water is made of oxygen, drinking more water increases the oxygen in our bodies. Drinking more water improves our body’s cellular respiration and the removal of toxins in our bodies. Essentially, water helps humans stay healthy, which can boost immunity and help avoid the flu. If you do happen to contract the flu, drinking plenty of water can help fight it and rid your body of the virus. Water is truly an amazing resource and does much more besides boosting our immune systems and helping prevent the flu. Whether it’s  flu season or not, drink plenty  of readily available tap water from your home faucet and keep hydrated. To learn about more benefits and tips to stay hydrated, read our post ‘New Year, New You: Benefits of Drinking Water

First built in 1949 to provide water to St. Bernadine Medical Center, the Perris Hill Reservoir serves as drinking water storage for the people in the City of San Bernardino. This hidden reservoir is not visible to the naked eye; it was intentionally constructed inside an existing hill, east of Perris Hill Park. A popular hiking spot for locals, the Perris Hill Reservoir is hidden deep in the earth. From the top of the hill, only the beautiful surrounding mountains of San Bernardino are seen. It is beneath this hilltop location where 10 million gallons of water are stored every day to provide a resource essential to all life; water. In 1962, the Perris Hill Reservoir was reconstructed to expand the capacity in order to meet the demands of the growing region.

Perris Hill Exterior

Perris Hill Reservoir is hidden beneath the soil at Perris Hill.

“In the 1940’s the need for additional water storage was identified. There wasn’t enough water for the hospital and the surrounding area,” stated Michael Garland, Water Utility Operations Superintendent at San Bernardino Municipal Water Department. “Because of its depth, Perris Hill Reservoir is technically classified as a dam by the State of California. There are many benefits to building a dam in a hill. Not only does it provide needed pressure to deliver water, but it also keeps the temperature cooler, versus an outdoor tank.”

The Perris Hill Reservoir, owned and operated by San Bernardino Municipal Water Department (SBMWD), is just one of 38 reservoirs operated by the Department. In 2016, SBMWD served 202,000 people, equating to 10.5 billion gallons of water.  The Perris Hill Reservoir provides water to 3,284 households.

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Rarely seen view of the interior of Perris Hill Reservoir after being drained.

Every eight years, the reservoir is drained for routine maintenance. The structure is disinfected, inspected and repairs are made. In January 2018, the Perris Hill Reservoir was drained and inspected. When the tank is empty, a large 20-inch pipe is visible on the floor of this damp, cool compound. This pipe is used to keep water moving inside the reservoir in order to minimize stagnation. Water enters the reservoir through the pipe; this is called the influent line. It leaves the pipe via another pipe called the effluent line. The constant movement helps ensure safe clean reliable water delivery to the consumers’ homes.

Perris Hill Reservoir Stairs

When the Perris Hill Reservoir is filled to capacity, water covers the entire staircase.

“Crews prepared for the draining of Perris Hill Reservoir by first determining the water demand of the reservoir. The water is not wasted, we simply shut off production from the well, so that no new water is entering the tank,” explained Garland. “We deplete the water from reservoir by the usage from our customers. Once the water is drained (used) we switch service so that the customers who would normally receive water from Perris Hill Reservoir receive water from another location. The entire process of draining takes approximately 10 days to complete.”

Perris Hill Reservoir does not have any on-site staff members who work at the location, however the monitoring of water levels and quality is logged multiple times a day. Daily water quality samples are collected and analyses are performed to ensure the safety of the drinking water.


Sensors help detect water levels inside the Reservoir.

“Our staff comes out to the site multiple times a day to report water levels and quality. Water levels can also be tracked remotely using a transducer, which uses sonar technology to report water levels,” shared Garland. “All of our facilities, including the Perris Hill Reservoir, record data relating to water supply using a computerized system for tracking real time data called Supervisory Control and Data Acquisition (SCADA).”

Viee Perris Hill Reservoir

View from the top of Perris Hill. The Perris Hill Reservoir sits just below this hilltop.

Water stored in the Perris Hill Reservoir comes from local water supplies, including groundwater basins and snowmelt from the San Bernardino Mountains. The San Bernardino area is a part of the Santa Ana River Watershed, an intricate system of natural water sources starting as snowmelt in the San Bernardino Mountains, traveling down through Riverside, then after multiple uses to Orange County for recharge into the groundwater via the Santa Ana River.


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