Frequently Asked Questions

Also see Additional Questions

1. What is Pure Water Monterey?

Pure Water Monterey is an advanced water recycling project, jointly developed by two public agencies – Monterey Peninsula Water Management District (MPWMD) and the Monterey One Water (M1W.) Pure Water Monterey is a multi-benefit, integrated, regional solution that will provide a water recycling model for other regions in California.

Using proven, advanced, multi-stage treatment to provide a safe, reliable and sustainable drinking water supply that will comply with or exceed strict state and federal drinking water standards, the project will reduce water taken from the Carmel River and the Seaside Basin. It also provides a source of tertiary treated water for the Salinas Valley agricultural industry while providing treatment for their impaired surface waters. In doing so, it will help meet regulatory orders and enhance water supply reliability by diversifying local water sources.

2. Why are the MPWMD and M1W considering this project?

In California (as well as other parts of the country and the world) water supplies are being stretched to the limit. The Monterey region is dealing with an adjudicated water basin and limited water supplies, stricter environmental constraints, and periodic droughts that will curtail unlimited use of our water supplies. Conserving and reusing this water resource instead of disposing of it in the ocean is efficient and provides a long term, sustainable water supply for our communities.

3. How does this project benefit the Monterey Peninsula?

An advanced water purification system would create a reliable, locally produced, ultra-pure water supply. In addition, this strictly regulated water supply would allow us to limit wastewater discharge into the delicate Monterey Bay Marine Sanctuary.

4. How does this project benefit the Salinas Valley?

Pure Water Monterey will not only deliver a drought-proof supply of potable water to reduce the current levels of groundwater pumping in the Salinas Valley, but it will also address the treatment of impaired agricultural surface waters.

5. What other communities use Advanced Water Purification technology?

Advanced Water Purification is used in many places around the world. As an example, Orange County California has operated a groundwater replenishment project since 1971. In this case, highly treated recycled water is used to prevent seawater intrusion into its aquifer by recharging it. Orange County produces 70 million gallons of purified water per day and is in the process of expanding production to 100 million gallons per day.

Other communities include Los Angeles; Inland Empire; Santa Clara, CA, Las Vegas, Nevada; Scottsdale, Arizona; and El Paso, Texas.

6. Is the technology safe?

The California Department of Health Services is charged with the responsibility for establishing uniform statewide reclamation criteria to ensure that the use of groundwater replenishment will not be detrimental to public health.

Pure Water Monterey will take treated wastewater and put it through an additional four-step treatment process of ozone pre-treatment, microfiltration, reverse osmosis, and oxidation with ultraviolet light and hydrogen peroxide. This process will make the water near distilled quality and exceeds all drinking water standards.

7. How does this project improve the water quality in the Seaside Aquifer?

The Pure Water Monterey project creates ultra-pure water. By adding this water into the groundwater it will, over time, increase the quality of the water as well as help to prevent seawater intrusion.

8. How does this project improve the water quality in the Salinas Valley Aquifer?

By supplying additional tertiary treated water to the Salinas Valley agricultural industry, it reduces the reliance on groundwater pumping thereby helping to combat the effects of seawater intrusion.

9. Do we need to identify new sources of drinking water?

Water providers throughout California are responsible for securing, managing and delivering a safe and reliable water supply to their regions. Searching for sustainable local water supply sources that match the right quality with the right use is part of that responsibility.

Many regions are looking for ways to meet long-term water supply demands. Recycled water is one new, locally developed and reliable water supply. Provided through proven technologies, it is a drought-resistant water supply that can help ensure safe, sustainable water now and into the future.

Recycled water is a locally controlled source, unlike imported water.

10. What about conservation?

Water conservation is always the first step in preserving the California’s water supplies. The 20×2020 Water Conservation Plan was adopted in 2008 to maximize the state’s urban water efficiency and conservation opportunities with a goal of a 20 percent per capita reduction in urban water demand by 2020. However, despite our best efforts, water conservation cannot meet all of our water demands.

11. What is wastewater?

Wastewater is water that has been previously used by a municipality that has suffered a loss of quality as a result of use. In homes, water is commonly used for washing our food, dishes, clothes and bodies, and for toilet flushing. The used water that goes down the drain or is flushed down the toilet is called wastewater. Because a considerable amount of water is used to carry away only a small quantity of waste, wastewater is mostly water.

12. What does “potable” mean, and what is potable reuse?

Potable water is drinking water. Potable reuse refers to reused water you can drink. It’s purified sufficiently to meet or exceed federal and state drinking water standards and is safe for human consumption.

13. What is the difference between indirect potable reuse and direct potable reuse?

How potable reused water is delivered determines if it is called indirect potable reuse or direct potable reuse.  Indirect potable reuse means the water is delivered to you indirectly.  After it is purified, the reused water blends with other supplies and/or sits a while in some sort of man-made or natural storage before it gets delivered to a pipeline that leads to a drinking water plant or distribution system. That storage could be a groundwater basin or a surface water reservoir. Direct potable reuse means the reused water is put directly into pipelines that go to a drinking water plant or distribution system.  Direct potable reuse may occur with or without “engineered storage” such as underground or above ground tanks.

14. Why is potable reuse an environmentally friendly option?

Potable reuse reduces the amount of wastewater discharged to creeks, rivers, bays, and oceans. It helps protect wildlife habitat by reducing the amount of water drawn from waterways. Additionally, it’s carbon footprint is much smaller than other water treatment options such as desalination.

15. What is advanced water purification?

Advanced water purification produces high-quality drinking water that is produced using the most advanced treatment processes available. Though technologies can vary, many systems use advanced water purification that includes three processes: microfiltration, reverse osmosis, and advanced oxidation with ultraviolet light. to ensure the purist possible water, Pure Water Monterey utilizes a fourth purification process, ozone pre-treatment.

Microfiltration involves passing wastewater through very fine hollow fiber membranes (about 1/300 the width of a human hair) which remove particulate matter, protozoa and some viruses. After passing through the membrane, the filtered water mostly contains dissolved salt and organic molecules.

Reverse osmosis (RO) involves forcing filtered water through a special membrane at high pressure to remove impurities such as dissolved salts, viruses, pesticides and most organic compounds. The membrane acts like an artificial kidney. RO produces water of a higher level of purity than drinking water. It is the same process used to desalinate seawater.

Advanced oxidation exposes the water to ultraviolet light combined with hydrogen peroxide to sterilize and eliminate remaining organic compound traces. The UV intensity is around 300 times that of the sun’s rays.

16. Is advanced purified water safe for drinking?

Yes, it is regulated to the same rigorous state and federal standards required for all drinking water.

17. How is water quality monitored?

Water is continuously monitored before and after treatment. Safeguards are built into the process to ensure that public health would never be compromised. If treatment is not performing properly, then investigations are conducted. If necessary, recycled water deliveries are suspended until the causes are identified and resolved.

16. What are the protective barriers in the water purification process?

The water purification process consists of several barriers to ensure sufficient reduction and/or elimination of the various contaminants that need to be controlled. As in all processes, monitoring is important in order to check that the processes are working properly and efficiently. Membrane filtration, reverse osmosis and advanced oxidation may be parts of a multi-barrier purification process; not all processes are needed in all situations.

18. What are the benefits using purified water for drinking?

The benefits of using purified water are many, but may vary in different regions. Benefits may include:

  • Decreased dependency on imported water
  • A locally controlled, reliable supply of high-quality water that is drought resistant
  • Sufficient water supplies to support economic vitality
  • High-quality water to replenish groundwater basins
  • Reduction of the amount of wastewater discharged to creeks, rivers and bays
  • A source of water for seawater intrusion protection
  • A more diversified water supply

19. Isn’t all water reused?

Yes, the water we use today has been used over and over again. Water reuse happens daily on rivers and other water bodies everywhere. If you live in a community downstream of another, chances are you are reusing its water and likewise communities downstream of you are most likely reusing your water. This has been called “de facto” or unacknowledged/unplanned potable reuse.

20. Who regulates recycled water? What laws and regulations have to be met?

In California, the permits for the use of recycled water are granted by the State Water Resources Control Board (SWRCB) and its nine Regional Water Quality Control Boards (RWQCB). In July of 2014 the regulatory authority was moved from the California Department of Public Health (CDPH) to the SWRCB, which now reviews and establishes water recycling criteria and regulations. These regulations are among the most stringent in the world. The permits incorporate these recommendations and also other conditions for the safe use of recycled water.

21. If purified water is so clean, why can’t we introduce it straight into the taps?

Regulations are currently under evaluation and development in California to ensure that public health will always be protected as these new potable reuse projects are being considered by communities.

22. Have large-scale studies been done on populations/ communities to investigate the effects of drinking advanced purified water?

Recycled water has been used to recharge underground aquifers and surface reservoirs in the United States for more than two decades. To date, there have been no adverse health effects from the use of recycled water.

23. Does the advanced water purification process remove pharmaceuticals and personal care products?

Existing water and wastewater treatment processes significantly reduce the levels of such substances and to date, state and federal regulatory authorities have not found cause to require further reductions.

Advanced water treatment processes that utilize membrane filtration, reverse osmosis, UV treatment and hydrogen peroxide remove contaminants to levels below concentrations of significance and can produce water qualities that are equal to or better than existing drinking water sources.

24. Can we have a presentation given to our community group?

Yes. Please call (831) 658-5652 or email to arrange for a presentation.

25. Can we take a tour of the wastewater treatment plant and the planned advanced water purificaton facilities?

Yes. Please call (831) 658-5652 to arrange a tour.