Los Angeles, CA USA

In partnership with Better Watts Initiative (BWI)

A collaboration between The Water Genome (formerly 501CTHREE) and the Better Watts Initiative results in 200,000 residents of Los Angeles public housing projects having their water tested and lead contamination issues addressed.

Download the full report here:

Dark Waters Impact Report 2024-11.pdf

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Environmental & Social Context

Watts is a densely populated, low-income community with high pollution burdens and significant health disparities, including a life expectancy 14 years shorter than nearby areas. Lead exposure is linked to cognitive and health impacts in the community, making water safety an environmental justice concern.

Study Objective

The study aimed to measure the presence and distribution of heavy metal contaminants—particularly lead—in residential tap water in Watts, Los Angeles, and to assess residents’ trust in tap water and information sources about water quality. It also sought to identify behavioral patterns (such as bottled water use and boiling practices) that could affect exposure risk and to inform policy recommendations for safer water infrastructure.

Methods

Researchers collected 530 household tap water samples (May–August 2023) and 184 surveys using community volunteers. Samples were taken from drinking taps without prior flushing and tested at UCLA for lead, copper, iron, and zinc against EPA standards. Dark Waters Impact

Water Quality Findings

Lead was detected in 21 samples (about 4% of households), with 5 samples exceeding the EPA action level of 15 ppb. Eight of the lead-positive samples were from public housing. Additionally, seven samples showed elevated copper or iron, which affect taste, smell, and color but are less immediately dangerous.

Resident Perceptions & Behaviors

Only 27.4% of residents drink unfiltered tap water, while 95.8% rely on bottled water, mainly due to contamination concerns and poor taste or odor. Trust is highest in community organizations and healthcare providers and lowest in the water utility. Many residents use boiling as a safety measure, although boiling can concentrate lead rather than remove it.

Interpretation of Findings

Dislike of water taste, smell, or color—rather than distrust of utilities—was the strongest factor associated with avoiding tap water. Because lead is colorless and tasteless, relying on sensory cues can create hidden exposure risks. The presence of detectable lead in 4% of homes, combined with widespread bottled water use, indicates both a public health concern and a financial burden on residents.

Policy & Community Impact

The study prompted local government action: Los Angeles officials ordered expanded lead testing across public housing and began planning remediation. The findings positioned approximately 200,000 public housing residents to receive broader testing and safer drinking water, demonstrating direct policy impact from community-based research.