Here is a comprehensive chart.

State	Covered Employers	Provisions	Medical or Recreational Marijuana Legal
Alabama	All	Testing permitted after applicant receives drug-testing policy and a conditional employment offer.	N/A
Alaska	All employers, including school districts or regional educational attendance areas.	Testing not restricted. Positive results or refusal may be grounds for not hiring.	Medical and Recreational
Arizona	All private employers, plus school districts and entities that furnish transportation to school districts.	Testing permitted after applicant receives drug testing policy. Refusal to submit to a drug test can be basis for not hiring. Testing is required for school bus driver certification.	Medical
Arkansas	N/A	No state laws; follows federal law where required.	Medical
California	State Agencies	Testing permitted for applicants to positions of sensitivity in state agencies if testing is job related. Testing is required for public transportation drivers.	Medical and Recreational
Colorado	N/A	No state laws; follows federal law where required.	Medical and Recreational
Connecticut	All private employers	Testing permitted after applicant receives drug-testing policy. Cannot test former employees unless they have been gone for at least 12 months. Testing is required for school bus driver certification.	Medical
Delaware	Public and private schools and school transportation; Department of Corrections.	Testing is required for school bus driver certification and for security positions at Department of Corrections.	Medical
District of Columbia	N/A	No state laws; follows federal law where required.	Medical and Recreational
Florida	Private employers with 3 or more employees. Public employers with safety-sensitive and law enforcement positions.	Testing permitted after applicant receives drug testing policy. Refusal to submit to a drug test can be basis for not hiring.	Medical
Georgia	State government employers, public schools, and companies that furnish school transportation; private employers.	Testing authorized for applicants of state government, public schools, and private companies. Refusal to submit to a drug test or a positive test result may disqualify applicant from state and public school employment for two years.	N/A
Hawaii	All employers	Testing permitted after applicant receives drug testing policy and has opportunity to disclose current prescription and nonprescription drugs being taken. Testing required for civil service applicants with city of Honolulu.	Medical
Idaho	All employers	Testing permitted.	N/A
Illinois	N/A	No state laws; follows federal law where required.	Medical
Indiana	N/A	No state laws; follows federal law where required.	N/A
Iowa	Public and private employers	Testing permitted if applicant is informed at the time of application that a drug test is required. Ads and applications must carry notice of drug test.	N/A
Kansas	State government	Testing permitted for applicants to safety-sensitive jobs after a job offer has been made. Ads for safety-sensitive jobs must carry notice of drug test.	N/A
Kentucky	N/A	No state laws; follows federal law where required.	N/A
Louisiana	Public and private employers not subject to a federally mandated testing program.	Testing not restricted.	Medical
Maine	Public and private employers	Testing permitted after applicant receives drug testing policy. Refusal to submit to a drug test or a positive test result can be basis for not hiring.	Medical and Recreational
Maryland	All employers	Testing not restricted.	N/A
Massachusetts	N/A	No state laws; follows federal law where required.	Medical and Recreational
Michigan	N/A	No state laws; follows federal law where required.	Medical and Recreational
Minnesota	Public and private employers	Testing permitted after applicant receives drug-testing policy and a conditional employment offer and only if all job candidates are tested.	Medical
Mississippi	Public and private employers	Testing not restricted.	N/A
Missouri	N/A	No state laws; follows federal law where required.	Medical
Montana	Public and private employers	Testing permitted for applicants to intrastate transport jobs, hazardous environments jobs, or positions with security, public safety, or fiduciary responsibility.	Medical
Nebraska	Private employers with six or more employees and public employers	Testing not restricted.	N/A
Nevada	State agencies	Testing permitted for public safety jobs. THC testing is not permitted for most jobs. Some professions are exempt: firefighters, emergency medical technicians (EMTs), any employee who drives a motor vehicle—for which federal or state law requires the employee to submit to a screening test—or any safety-sensitive position that could adversely affect the safety of others.	Medical and Recreational
New Hampshire	N/A	No state laws; follows federal law where required.	Medical
New Jersey	N/A	No state laws; follows federal law where required.	Medical
New Mexico	N/A	No state laws; follows federal law where required.	Medical
New York	N/A	New York City bans pre-employment screening for marijuana use except for safety and security sensitive jobs and jobs bound by a federal or state contract or grant.	Medical
North Carolina	Public and private employers	Testing not restricted.	N/A
North Dakota	N/A	No state laws; follows federal law where required.	Medical
Ohio	All employers	Applicant testing authorized with advance notice to applicant and after offer of employment has been made.	Medical
Oklahoma	Public and private employers	Applicant testing authorized with advance notice to applicant and after offer of employment has been made. Notice must be in writing, describing methods, procedures, and policies in detail.	Medical
Oregon	All employers	Testing permitted if reasonable suspicion exists that applicant is under the influence of alcohol or controlled substance.	Medical and Recreational
Pennsylvania	N/A	No state laws; follows federal law where required.	Medical
Rhode Island	Public and private employers	Private sector applicant testing permitted only after offer of employment has been made. Public sector testing permitted for jobs involving public safety or when required by federal law.	Medical
South Carolina	All employers S.C. Code § 1-13-30.	Testing not restricted.	N/A
Tennessee	State Dept. of Corrections	Testing not restricted.	N/A
Texas	N/A	No state laws; follows federal law where required.	N/A
Utah	Private employers, local government entities, and state institutions of higher education	Testing not restricted in the private sector. Local governments and state colleges can test applicants with advance notice and a written policy. Refusal to submit to a drug test or a positive test result can be basis for not hiring.	Medical
Vermont	Public and private employers	Testing authorized with advance written notice to applicant, after conditional offer of employment has been made, and if test is part of pre-employment physical.	Medical and Recreational
Virginia	N/A	No state laws; follows federal law where required.	N/A
Washington	Private employers seeking to qualify for a 5% workers’ comp. premium discount, with approval by state authorities.	Testing authorized with advance written notice and after conditional offer of employment has been made.	Medical and Recreational
West Virginia	N/A	No state laws; follows federal law where required.	Medical
Wisconsin	N/A	No state laws; follows federal law where required.	N/A
Wyoming	N/A	No state laws; follows federal law where required.	N/A

Hope this helps!

October 2018

Drug testing

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state drug testing laws

drug testing by state

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Where can I find drug testing laws by state?