The Santiago Basins are a group of groundwater recharge facilities along Santiago Creek in Orange and Villa Park, California. Operated by the Orange County Water District (OCWD), the system includes Smith Basin, Blue Diamond Basin and Bond Basin. The basins capture and store water that can percolate into the Orange County Groundwater Basin while also providing storage for storm flows.
Santiago Basins at a Glance
- Operator: Orange County Water District
- Waterway: Santiago Creek
- Basins: Smith, Blue Diamond and Bond
- Communities: Villa Park and Orange
- Primary purpose: Groundwater recharge and stormwater capture
- Public water access: No
What Are the Santiago Recharge Basins?
The Santiago Basins are downstream of Villa Park Dam in Orange and Villa Park. The three former sand and gravel pits are part of OCWD’s groundwater recharge system. Water reaching the basins can include stormwater from Santiago Creek as well as water moved through OCWD’s recharge system from the Santa Ana River.
The basins provide valuable storage within OCWD’s recharge network. Rather than sending water directly from the basins to customers, OCWD allows water to infiltrate through the basin bottoms and replenish the groundwater aquifer below.
How Groundwater Recharge Works
Water stored in the Santiago Basins gradually percolates through the soil into the Orange County Groundwater Basin. Water agencies throughout the region then pump groundwater from wells and treat and distribute it as part of their local water supplies. OCWD manages its recharge facilities to capture available water, increase groundwater replenishment and maintain storage capacity for storm flows.
Smith, Blue Diamond & Bond Basins
| Basin | Location |
|---|---|
| Smith Basin | Northern basin near Villa Park, north of Villa Park Road |
| Blue Diamond Basin | Central basin south of Villa Park Road |
| Bond Basin | Southern basin near Hewes and Bond streets in Orange |
OCWD generally refers to the group as the Santiago Basins. Other informal or mapping references may use Santiago Creek Recharge Basin or Santiago Creek Basin.
Why Water Levels in the Santiago Basins Change
Water levels can change significantly as OCWD moves, stores and recharges water. The basins may also be lowered to create storage capacity for winter storm flows, improve stormwater capture and increase groundwater recharge. As a result, a basin that appears full at one time of year may look considerably lower at another.
Santiago Reservoir vs. Santiago Basins
Santiago Reservoir is not the same facility as the Santiago recharge basins. Santiago Reservoir, commonly known as Irvine Lake, is upstream behind Santiago Dam. The Santiago Basins are downstream groundwater recharge facilities operated by OCWD. Villa Park Dam is another separate flood-control facility along Santiago Creek.
Villa Park Drinking Water
Villa Park is served by Serrano Water District. Its water supply includes groundwater pumped from local wells, imported Metropolitan Water District water and local surface-water resources associated with Irvine Lake. Groundwater used by the district is part of the larger regional groundwater system managed by OCWD.
Serrano Water District’s water-supply arrangements have continued to evolve. In January 2025, the district transferred its 25% ownership interest in Santiago Reservoir/Irvine Lake to Irvine Ranch Water District as part of an agreement that includes a future backup water-supply connection. For current information about Villa Park’s drinking water, see Serrano Water District.
Santiago Basin History
The Santiago Basins are former sand and gravel pits that OCWD developed as groundwater recharge facilities. Historically, runoff from Santiago Creek was the primary source of water reaching the basins. The recharge system was later expanded so water could also be moved between the Santa Ana River recharge facilities and the Santiago Basins.
The surrounding area’s history reaches back to the 1870s, when Oge and Bond formed the Oge-Bond Tract. The Bond name remains prominent locally, including Bond Basin and nearby Bond Street.
1983
OCWD purchased two sand and gravel pits along Santiago Creek for additional recharge capacity.
1991
The Santiago Creek recharge project was completed, including development of the Santiago Basins, a pump station at Burris Basin and a pipeline allowing water to be conveyed between recharge basins along the Santa Ana River and the Santiago Basins. Improvements to Santa Ana River diversion facilities also increased OCWD’s ability to capture water for groundwater recharge.
2003
An underwater pump station was installed in Bond Basin to increase operational flexibility and recharge capacity. The Santiago Basin Pump Station enabled OCWD to move water in both directions through the Santiago Pipeline, helping lower the basins when additional storage was needed for stormwater capture.
2012
The underwater pump station was replaced by a floating pump station. The floating station was designed to dewater the Santiago Basins, increase storm-flow capture and percolation, make storage available for winter use and transfer stored water to other OCWD facilities.
2024–Present
OCWD has continued investing in the Santiago Basin pumping infrastructure. Recent capital planning included refurbishment of the floating pump station and associated controls, drives, piping, wiring and floating components. Current operating status should be confirmed with OCWD as improvements are completed.
Wildlife Around Santiago Creek
The Santiago Creek corridor and surrounding open space support a wide range of wildlife and bird species. Birds observed in the broader area include turkey vultures, doves, hawks, hummingbirds, woodpeckers, egrets, herons, sparrows and quail.
OCWD has documented wildlife habitat associated with its recharge facilities, including Western Grebes and the threatened coastal California gnatcatcher in nearby shrub habitat. Wildlife observations vary by season, water levels and habitat conditions.
For broader local bird observations, see the eBird Santiago Basin hotspot.
Fishing, swimming and public access to the recharge basins are prohibited. Visitors should view the basins only from authorized public trails and viewing areas.
Where to View the Santiago Basins
The Santiago Creek Bike Trail provides some of the best legal public views of the basins. Viewing areas are available along portions of the trail near Hewes Street and Bond Street, while the Cannon Street staging area also provides views of the Santiago Creek corridor. Drivers can also see portions of the basins from public roads, including Villa Park Road.
The Santiago Basins & Orange County Groundwater
The Santiago Basins are one component of OCWD’s much larger groundwater recharge system serving north and central Orange County. OCWD replenishes the groundwater basin with stormwater, Santa Ana River water and highly purified recycled water from the Groundwater Replenishment System (GWRS). Together, these sources help maintain a reliable regional groundwater supply.
Santiago Creek Recharge Basin FAQs
What are the Santiago Creek Recharge Basins?
They are three groundwater recharge basins along Santiago Creek operated by the Orange County Water District. Water stored in the basins can percolate into the Orange County Groundwater Basin.
Where are the Santiago Basins?
The basins are located along Santiago Creek in the cities of Villa Park and Orange, downstream of Villa Park Dam.
What are Smith, Blue Diamond and Bond basins?
Smith, Blue Diamond and Bond are the three individual basins that make up OCWD’s Santiago Basins recharge facilities.
Why do water levels in the Santiago Basins change?
OCWD moves and recharges water through the system and may lower basin levels to create storage for winter storms and additional groundwater recharge.
Can you fish or swim in the Santiago Basins?
No. The recharge basins are operating water facilities and public access, fishing and swimming are prohibited.
Is Santiago Reservoir the same as the Santiago Recharge Basins?
No. Santiago Reservoir, also known as Irvine Lake, is upstream behind Santiago Dam. The Santiago Basins are separate downstream groundwater recharge facilities operated by OCWD.