Rock Creek Water District

What it means: Community water systems must deliver an annual water quality report (Consumer Confidence Report) to all customers by July 1, covering the previous year. It must list all detected contaminants, compare them to MCLs, identify source water, and include educational language about lead. A violation means the report was not delivered on time or was incomplete.

Health effects: No direct health risk — this is an administrative transparency obligation. Failure means customers lack information to make informed decisions (e.g., whether to use bottled water for infants when lead is elevated).

Limit: No MCL — this is a reporting requirement

What it means: The Interim Enhanced Surface Water Treatment Rule (IESWTR), finalized in 1998, strengthened protections for systems serving 10,000 or more people by tightening turbidity limits and requiring Cryptosporidium removal. It was an intermediate step between the original SWTR and the Long-Term Enhanced SWTRs.

Health effects: Violations indicate failure to meet treatment technique requirements that reduce exposure to Cryptosporidium, Giardia, and other microbial pathogens. Cryptosporidium poses the greatest risk to immunocompromised individuals, infants, and the elderly, and can cause severe or fatal illness in vulnerable populations.

Limit: Treatment technique — no numeric MCL; compliance means meeting turbidity limits (0.3 NTU in 95% of monthly samples) and Cryptosporidium removal benchmarks

What it means: When a system violates a drinking water standard, it must notify customers promptly: within 24 hours for acute violations (e.g., E. coli), 30 days for non-acute MCL violations, and 1 year for monitoring failures. A violation means the notification was late or missing — not that the underlying water issue is necessarily severe.

Health effects: No direct health risk from the notification violation itself, but delayed notification means customers may have consumed contaminated water without the chance to take protective action (boil water orders, bottled water use).

Limit: No MCL — compliance requires meeting specific notification deadlines

What it means: All systems using surface water (rivers, lakes, reservoirs) or groundwater under surface influence (GWUDI) must filter and disinfect. Treatment technique violations mean the system failed to maintain adequate disinfectant residual, exceeded turbidity limits, or lacked required permits. Snowmelt and storm events can raise turbidity and pathogen loads in surface water.

Health effects: Without proper filtration/disinfection: Giardia lamblia (severe diarrhea, cramping), Cryptosporidium (life-threatening for immunocompromised individuals), viruses (hepatitis A, norovirus). Turbidity itself is not a health risk but can shield pathogens from disinfection.

Limit: Treatment technique: turbidity ≤0.3 NTU in 95% of monthly samples; detectable disinfectant residual in 95% of distribution samples