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Decision playbook · Source-water concern

Find the Drinking-Water System and Report a Lake or Reservoir Source-Water Concern

Find the supplying system and responsible authorities, document a concern safely, protect infrastructure information, and preserve a source-to-tap handoff without declaring contaminant identity or tap safety.

For
Drinking-water utilities, source-water coordinators, Tribes, primacy agencies, watershed organizations, public-health and emergency partners, lake managers, laboratories, consultants, and community monitoring programs
Reading time
20 minutes
Reviewed
Next review
Direct answer

What to do first

For an urgent exposure, active release, illness, infrastructure, or service concern, use current emergency and utility channels first. Otherwise document the observation safely without approaching an intake or improvising sampling. Identify whether the lake or reservoir supplies a public water system or another intake, then find the utility, primacy, Tribal, environmental, health, and emergency authorities. Keep source, raw, treated, finished, distribution, and tap-water evidence separate. A source-water result does not establish tap safety, a visible condition does not identify a contaminant or health risk, and the absence of a notice does not mean safe. Protect precise intake, infrastructure, customer, and response information; preserve current-source provenance, report IDs, acknowledgements, utility notices, limitations, corrections, and closure. LakeTech does not issue or lift a drinking-water advisory or direct intake, treatment, or customer action.

Use this guide to
  • Route urgent conditions first
  • Identify the supplying system and authorities
  • Preserve source-to-tap evidence classes
  • Document without unsafe approach or sampling
  • Protect infrastructure and personal information
  • Track attributable notices and corrections

1. Protect people and use the utility or emergency branch first

Immediate protection and utility direction precede source-water investigation.

For an exposure, illness, active release, security event, or urgent service concern, move to safety and use current emergency, utility, primacy-agency, or public-health channels. LakeTech does not issue or lift drinking-water advisories and does not direct intake, treatment, boiling, flushing, filtering, dilution, or customer use.

Sources: [7], [16]

2. Separate source, raw, treated, finished, distribution, and tap water

Water location and treatment state control what evidence can support.

Label every observation or result as lake source water, intake-zone water, raw water, treatment-process water, finished water, distribution water, or tap water. A source-water result is not a tap-safety determination, and a finished-water result does not establish the lake's condition.

Sources: [1], [17]

3. Determine whether the lake supplies a public system or another intake

Do not assume that a visible intake identifies a regulated public system.

Use current utility, primacy, Tribal, owner, and public records to determine the supplying system, intake purpose, service area, and responsible operator. Record unresolved identity rather than inferring ownership or current operation from a map layer.

Sources: [9], [10], [13]

4. Identify the utility, primacy, environmental, health, and emergency authorities

Each decision remains with its responsible authority.

Create attributable current contacts for utility operations, drinking-water primacy, environmental response, public health, Tribal jurisdiction, landowner access, and emergency response. Federal guidance does not replace a local requirement or responsible authority.

Sources: [9], [13], [8]

5. Document the concern without unsafe approach or improvised sampling

Observation-only and no-sample branches are valid.

From a safe and lawful position, record time, generalized location, observable condition, weather, photographs, access limits, and who was notified. Do not approach an intake, enter restricted infrastructure, sample unknown material, contain a release, or collect water without exact authorization and a controlling safety and quality plan.

Sources: [7], [18]

6. Protect intake, infrastructure, customer, and response-location information

Operationally useful records may require restricted handling.

Classify exact intake coordinates, treatment vulnerabilities, customer information, responder locations, access routes, and infrastructure details before sharing. Use generalized public locations and preserve an accountable restricted record for authorized users.

Sources: [6], [10]

7. Classify the observed concern without naming a contaminant or health risk

Observation categories are not analytical or medical conclusions.

Describe odor, color, sheen, debris, runoff, dead organisms, bloom-like material, damage, or a reported release as observations with limitations. Do not convert appearance, proximity, or a single screening result into contaminant identity, exposure, health risk, culpability, or compliance.

Sources: [12], [19]

8. Find current source-water assessment, utility information, and data provenance

Public portals are discovery evidence, not complete real-time system status.

Retrieve the current source-water assessment or protection record where available, preserve publisher, query, filters, access date, version, spatial and temporal scope, and limitations, and distinguish DWMAPS, WQP, ATTAINS, How's My Waterway, USGS, state, Tribal, and utility records. A CCR or portal is not real-time source status and database absence does not prove compliance or absence.

Sources: [11], [10], [21], [15], [14]

9. Notify through attributable channels and preserve shared event handoff

A report starts a handoff; it does not decide the outcome.

Record recipient, channel, timestamp with offset, case or incident ID, evidence transmitted, acknowledgement, instructions, open notifications, and next owner. Preserve the source-to-tap evidence class and avoid publishing sensitive infrastructure or response details.

Sources: [7], [8]

10. Track utility notices, corrections, and closure without issuing LakeTech advice

Only the responsible authority controls customer direction and closure.

Link utility and authority notices to exact issuer, scope, effective time, revision, supersession, and withdrawal. LakeTech may reproduce attributable status with limitations but does not issue, reinterpret, expand, or lift a drinking-water advisory.

Sources: [16], [9]

Evidence base

Sources and review notes

Educational source-water protection, evidence-control, and preparedness guidance only. It is not a tap-water safety determination, drinking-water advisory, contaminant identification, regulatory finding, emergency-response plan, treatment instruction, intake operating instruction, permit, funding award, or authorization. Current utility, primacy-agency, public-health, emergency, Tribal, federal, state, territorial, local, landowner, laboratory, security, privacy, access, sampling, and public-communication requirements control.

  1. Basic Information about Source Water ProtectionU.S. Environmental Protection Agency · agency guidance
  2. Assess, Plan and Protect Source WaterU.S. Environmental Protection Agency · agency guidance
  3. Source Water Protection PlanningU.S. Environmental Protection Agency · agency guidance
  4. Source Water Protection PracticesU.S. Environmental Protection Agency · agency guidance
  5. Evaluate Progress Toward Source Water Protection GoalsU.S. Environmental Protection Agency · agency guidance
  6. Common ConsiderationsU.S. Environmental Protection Agency · agency guidance
  7. Preparing for EmergenciesU.S. Environmental Protection Agency · agency guidance
  8. Incident Action Checklist: Source Water ContaminationU.S. Environmental Protection Agency · reference
  9. Primacy Agency Drinking Water DataU.S. Environmental Protection Agency · reference
  10. DWMAPS User GuideU.S. Environmental Protection Agency · reference
  11. Resources for Source Water AssessmentsU.S. Environmental Protection Agency · reference
  12. Types of Drinking Water ContaminantsU.S. Environmental Protection Agency · reference
  13. Tribal Governments' Role in Safe Drinking Water in Indian CountryU.S. Environmental Protection Agency · agency guidance
  14. How's My WaterwayU.S. Environmental Protection Agency · reference
  15. Assessment, Total Maximum Daily Load Tracking and Implementation SystemU.S. Environmental Protection Agency · reference
  16. Water Decontamination Frequently Asked Questions for CustomersU.S. Environmental Protection Agency · agency guidance
  17. Long Term 2 Enhanced Surface Water Treatment Rule DocumentsU.S. Environmental Protection Agency · reference
  18. Quality Assurance Project Plan StandardU.S. Environmental Protection Agency · field protocol
  19. Drinking Water and Source Water ResearchU.S. Geological Survey · reference
  20. Lakes and Reservoirs: Guidelines for Study Design and SamplingU.S. Geological Survey · field protocol
  21. Water Quality PortalNational Water Quality Monitoring Council · reference