Service areas

Mobile Drug & Alcohol Testing | National Reach, Local Response.

OnSite Employer Testing is a mobile and on-site employer testing provider: collectors come to your workplace or job site on a schedule that matches your DOT or non-DOT program—not a retail walk-in clinic model. We support employers in major metro counties nationwide; this page lists representative service areas and coverage anchors. It does not replace the services hub (modalities, panels, and program types)—use both when you scope work with HR, safety, or your DER.

Whether you are aligning random batches, hiring surges, or incident-driven collections, geography matters: drive time, collector capacity, and site access shape what we can commit to on a given day. The counties below are markets where we routinely plan employer-directed field collections—not a guarantee of same-day service everywhere, but a clear picture of where our operational focus intersects with employer demand.

For how we think about distance, dispatch, and multi-site programs in general, see Coverage & service areas.

Counties we serve

Twenty counties across twelve states, grouped below.

Don't see your county?

Request national dispatch or confirm coverage.

Request coverage Call (219) 315-0345

Illinois

Chicagoland warehousing, freight, and intermodal activity.

Kane County, IL
Cook County, IL
DuPage County, IL
Will County, IL

Indiana

Indianapolis metro ties statewide employer sites to major interstate corridors.

Marion County, IN

Texas

Houston-area port freight and Dallas–Fort Worth industrial logistics corridors.

Harris County, TX
Dallas County, TX

California

Inland Empire and Southern California logistics flow between ports and warehouse networks.

Los Angeles County, CA
San Bernardino County, CA

Tennessee

Memphis rail and highway crossroads for Mid-South distribution employers.

Shelby County, TN

Georgia

Atlanta metro anchors Southeast freight lanes and large-employer volume.

Fulton County, GA

Arizona

Phoenix metro industrial markets along major Sun Belt interstate routes.

Maricopa County, AZ

Florida

I-4 corridor and coastal metros with strong employer and distribution activity.

Miami-Dade County, FL
Hillsborough County, FL
Duval County, FL

New York

Dense NYC-area worksites across boroughs and Long Island.

Suffolk County, NY
Queens County, NY

Pennsylvania

Lehigh Valley industry and highways linking Philadelphia and New York markets.

Lehigh County, PA

Ohio

Columbus metro as a central Ohio employer node on east–west freight routes.

Franklin County, OH

North Carolina

Charlotte regional distribution and interstate access for Carolinas employers.

Mecklenburg County, NC

Not in one of our primary service areas?

Our National Dispatch team may still be able to coordinate mobile testing through our trusted partner network, depending on location, scheduling, and program requirements.

Request coverage Call (219) 315-0345

Availability by market and program

Service availability, scheduling windows, response times, and test modality options can vary by market, season, and the specifics of your employer program (DOT vs non-DOT, observed collections, alcohol sequencing, after-hours needs, and site access rules). What holds in one county on one day may need a different plan across state lines or during a hiring peak.

The reliable path is to share your locations, policy context, and timelines so we can answer with operational specifics—not a generic promise that ignores chain-of-custody and program rules.

Next step with your locations in mind

Request a quote with sites and program type, continue the coverage conversation, or contact us to confirm service availability before you authorize a collection.

Request a quote Talk about coverage Confirm service availability