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1. What is TCP?

1,2,3-Trichloropropane (TCP) is a chemical that was an unnecessary ingredient in agricultural soil fumigants applied to farm fields from the 1950s to the 1980s. After being applied to the ground over many years, TCP has migrated down into our groundwater and has been detected in several District wells. The State Water Resources Control Board, Division of Drinking Water (DDW) says that, while TCP levels in our water do not pose a health emergency and there is no need to use an alternative (e.g. bottled) water supply, some people who drink water containing TCP over many years may have an increased risk of cancer, based on studies of laboratory animals.

2. What is Monte Vista Water District doing about TCP?

The District is committed to providing high quality drinking water that meets or exceeds all state and federal water quality standards at all times. As such, the District has stopped pumping certain wells where TCP has been detected and is in the process of designing and constructing treatment facilities to remove TCP from the water before it is made available to our customers.

3. How is TCP removed from the water?

TCP can effectively be removed using granular-activated carbon (GAC) technology. GAC is also recognized by the State of California as the "best available technology" to remove TCP and is the exact technology that the District will be implementing to remove TCP.

4. Where can I learn more about Monte Vista Water District's water quality?

We encourage you to review our most recent Annual Water Quality Report (PDF). For additional questions or requests for further information, call 909-624-0035, ext. 185.

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1. What is the Plant 30 Wellhead Treatment Project?

Monte Vista Water District is committed to providing high quality drinking water that meets or exceeds all state and federal water quality standards at all times. MVWD will add granular-activated carbon (GAC) and ion exchange technology to the water treatment process at Plant 30, located on San Bernardino St. in Montclair, to meet stricter regulations recently implemented by the State Water Resources Control Board’s Division of Drinking Water (DDW). The project will include 12 GAC vessels, each approximately 10’ in diameter and 18’ tall, as well as four slightly larger ion exchange vessels. 

2. Why is the treatment process necessary?

The State Water Resources Control Board’s Division of Drinking Water (DDW) now requires advanced treatment of drinking water for 1,2,3-Trichloropropane (TCP).  TCP is a chemical that was an unnecessary ingredient in agricultural soil fumigants applied to farm fields from the 1950s to the 1980s.  After being applied to the ground over many years, TCP has migrated down into our groundwater and has been detected in some District wells.

3. How does this process differ from MVWD's other treatment processes?

The water distributed by Monte Vista Water District that our customers receive at their taps meets or exceeds all state and federal drinking water standards set to protect public health. Groundwater produced by MVWD’s wells requires very minimal treatment prior to distribution. However, the groundwater basin from which MVWD draws water has areas of high concentration of nitrates, a salt that at certain levels may pose a health risk to vulnerable populations. MVWD currently uses ion exchange treatment to remove nitrates from the pumped groundwater.  The Plant 30 Wellhead Treatment Project will add granular-activated carbon (GAC), which is recognized by the State of California as the “best available technology” to remove TCP and improve drinking water quality for MVWD customers.

4. What is the anticipated timeline for construction of the Plant 30 Wellhead Treatment Project?

Construction of the treatment project is anticipated to begin October 2020 and could last approximately 12 months. Much of the construction project will occur on MVWD’s Plant 30 site, located on San Bernardino St. in Montclair. Pipelines will also be installed along Benson Ave., between Palo Verde St. and Orchard St., to distribute water from two other MVWD wells to be treated at this facility. MVWD staff are working very closely with the cities of Montclair and Ontario as well as the Ontario-Montclair School District to coordinate construction and reduce impacts to residents and nearby schools.