California is directing $46 million of voter-approved Proposition 4 funding toward worsening Tijuana River water quality and New River contamination at the US-Mexico border. The funding was opened for applications by the State Water Resources Control Board in June 2026.
Eligible projects include those that reduce bacteria and trash loads, address public health impacts, and support sediment management and habitat restoration along both rivers. Planning and research grants are capped at $750,000, while implementation grants can reach $10 million, or up to $20 million with additional approval.
A federally managed wastewater treatment plant near San Ysidro treats cross-border flows from the Tijuana River but has historically struggled to keep pace with the volume and condition of the water it receives. Independent analysis published in The Water Report traces the roots of the crisis to Tijuana's sewage collection system, which remains incomplete after decades of growth that has outpaced infrastructure investment (see TWR #254 for more background).
Applications for the grant program are being accepted from June 11 through August 31.
