Water Quality Update – July 2025

Santa Margarita Water District (SMWD) would like to inform its customers of an upcoming temporary change in the blend of water delivered to its service area. SMWD receives imported water from the Metropolitan Water District of Southern California (Metropolitan), through the Municipal Water District of Orange County (MWDOC). Metropolitan has provided the following update regarding water treatment operations at the F.E. Weymouth and Robert B. Diemer Water Treatment Plants, which may impact the water supplied to our area in South Orange County.

To accommodate a scheduled maintenance outage of the Lake Mathews forebay, Metropolitan will temporarily adjust the blend of water sources at the Weymouth and Diemer plants. Specifically, the percentage of California State Water Project (SWP) water will gradually increase from 40% to 100% between July 9 and July 19, 2025. It will remain at 100% SWP until July 27. Following the completion of the maintenance, the blend will gradually decrease back to 40% between July 28 and August 4, where it will remain until further notice.

Please be assured that all water delivered during this time will continue to meet or surpass all state and federal water quality standards. This update is informational only, and no action is required by customers. SMWD remains committed to delivering high-quality drinking water to our community and will provide further updates if any changes occur.

How These Water Source Changes May Affect Your Drinking Water
During the period of increased State Water Project (SWP) water use-from July 9 to July 27, 2025-some customers may notice slight and temporary changes in the taste or odor of their drinking water. This is due to the natural differences between SWP water and Colorado River water, which are normally blended at lower ratios. SWP water typically has lower mineral content and a different composition of naturally occurring organic materials compared to Colorado River water.

While these differences are purely aesthetic, such as a slightly different taste or smell, they do not affect water safety or quality. The water continues to meet or exceed all federal and state drinking water standards.

Once the maintenance is complete and the blend returns to normal levels, any noticeable changes should gradually subside.

SMWD Customer Care
If customers have sensitive palates or use water for specific needs (like aquariums, home brewing, or kidney dialysis), they may wish to consult a professional or contact SMWD's water quality team for additional guidance during this time. You may contact SMWD's Customer Care team at [email protected] or (949) 459-6420.

Santa Margarita Water District remains committed to ensuring the highest water quality for all our customers and will continue to closely monitor these changes.

Resources:
Learn more about SMWD's water quality.
SMWD Water Quality Reports (SMWD.com/WaterQuality)