A D6 clearance is a Department of Defense security clearance that allows access to Secret-level classified information

The "D" stands for Department of Defense, and the "6" is the numerical code for Secret clearance — the middle tier of the three main security clearance levels. If you hold a D6, you can access Secret information but not Top Secret or higher. It is less restrictive than a Top Secret clearance but more restrictive than a Confidential one, and it is the most common clearance held by federal contractors and military personnel.

A D6 clearance is not something you request on your own. Your employer — usually a defense contractor, military branch, or federal agency — requests it on your behalf because a specific job requires access to Secret information. The clearance is tied to that job and that employer. If you change jobs, your clearance does not automatically transfer, though the process to transfer or renew it is often faster than obtaining one from scratch.

Key Takeaways

  • D6 clearance is a Department of Defense Secret-level clearance that sits between Confidential and Top Secret in terms of access and scrutiny.
  • Your employer must request the clearance for you; you cannot initiate the process yourself, and the clearance is tied to that specific job.
  • The background investigation for a D6 includes a credit check, criminal history review, and interviews with people who know you, but typically does not include a polygraph test.
  • The clearance process usually takes three to six months from start to approval, though timelines vary based on the volume of cases and the completeness of your paperwork.
  • Once granted, a D6 clearance is valid for ten years and requires periodic reinvestigation to maintain it.

How a D6 clearance differs from Confidential and Top Secret

The three main security clearance levels are Confidential, Secret, and Top Secret. Confidential is the lowest and allows access to information that could damage national security if disclosed. Secret — the D6 level — covers information that could cause serious damage. Top Secret covers information that could cause exceptionally grave damage. The higher the level, the more thorough the background investigation and the longer the process takes.

A D6 clearance requires a more detailed background check than Confidential but less intensive scrutiny than Top Secret. For a D6, investigators will examine your financial history, criminal record, drug use, foreign contacts, and personal conduct. They will interview people who know you — former employers, neighbors, family members — to assess your reliability and trustworthiness. A Top Secret clearance involves all of this plus a polygraph examination and often a more exhaustive review of your entire life history.

The cost difference is significant. A Confidential clearance costs the government roughly $3,000 to $5,000 to investigate. A D6 (Secret) clearance costs between $5,000 and $15,000. A Top Secret clearance can exceed $15,000 and sometimes reaches $30,000 or more. These are estimates and vary by agency and circumstance, but they reflect why employers are selective about who they request clearances for.

What the background investigation includes

When your employer requests a D6 clearance, you will be asked to complete a form called the SF-86 (Questionnaire for National Security Positions). This form asks for your complete employment history, education, residences for the past seven years, foreign travel, financial obligations, criminal history, and drug use. You must be thorough and honest; omissions or false statements can result in clearance denial or, if discovered later, criminal charges for making false statements to the federal government.

After you submit the SF-86, an investigator from the Defense Counterintelligence and Security Agency (DCSA) or a contracted investigation firm will conduct interviews. They will speak with former employers, colleagues, neighbors, and sometimes family members. They will pull your credit report and criminal history. They will verify your employment dates and educational credentials. They will check whether you have any foreign contacts or financial problems that could make you vulnerable to coercion or bribery.

Unlike a Top Secret clearance, a D6 investigation does not typically include a polygraph test. However, if the investigator uncovers concerning information — unexplained debt, undisclosed foreign contacts, or inconsistencies in your statements — they may request additional interviews or documentation, which can extend the timeline.

How long the clearance process takes

From the moment your employer submits your clearance request to the day you receive approval typically takes three to six months. This timeline assumes your paperwork is complete and accurate, and that investigators do not uncover issues requiring follow-up. If you have lived abroad, have extensive foreign contacts, or have a complicated financial history, the process can take longer — sometimes nine months to a year or more.

The timeline also depends on the current workload of the DCSA and contracted investigators. During periods of high demand — such as after a major defense contract award or military expansion — processing can slow. You will not have much visibility into where your case stands during this period. Your employer's security officer or facility security officer (FSO) can sometimes request a status update, but the government does not provide regular progress notifications to the individual.

Once your clearance is granted, you will receive a clearance certificate or notification. Your employer will be notified as well. You can then access Secret-level information as required by your job. The clearance remains valid for ten years, after which it must be renewed through a periodic reinvestigation.

What can disqualify you from obtaining a D6 clearance

The government uses thirteen adjudicative guidelines to evaluate clearance requests. These cover criminal conduct, financial irresponsibility, alcohol or drug use, mental health, foreign influence, sexual conduct, and other factors. You do not need a perfect history to obtain a clearance, but you do need to demonstrate that any past issues have been resolved and that you are trustworthy.

Common reasons for clearance denial include unresolved criminal charges, a pattern of financial delinquency or fraud, active substance abuse, undisclosed foreign contacts or family members, or a history of dishonesty. A single mistake — such as a DUI from ten years ago or a period of credit card debt — does not automatically disqualify you if you can show it was an isolated incident and you have since corrected course. However, a pattern of behavior or an attempt to hide information is much more serious.

If your clearance request is denied, you have the right to request a hearing before a Defense Office of Hearings and Appeals (DOHA) administrative judge. You can present evidence and witnesses to challenge the denial. Many people successfully overturn initial denials at this stage, particularly if they can demonstrate that circumstances have changed or that the investigator misunderstood their situation.

Maintaining your clearance and what happens if you leave your job

Once you have a D6 clearance, you are responsible for reporting any significant changes in your life — a criminal arrest, a major financial problem, a foreign contact, a change in drug use, or a mental health crisis. Failure to report these changes can result in clearance revocation. Your employer will also conduct periodic reinvestigations, typically every ten years for a Secret clearance, though some agencies reinvestigate more frequently.

If you leave your job, your clearance does not disappear when ready, but it becomes inactive. If you move to another job that requires a clearance — whether with a different contractor or a government agency — your new employer can request that your clearance be transferred or reinstated. This process is faster than obtaining a new clearance from scratch because the investigation is already complete. However, if you have been out of the cleared workforce for more than two years, or if significant time has passed since your last investigation, your new employer may request a new full investigation rather than a reinstatement.

Some people maintain an inactive clearance for years after leaving a cleared job, which can be useful if they return to the field. However, if you have had major life changes — a move abroad, a significant financial crisis, or a criminal incident — those changes will be scrutinized during reinstatement, just as they would be during a new investigation.

The difference between a D6 clearance and other clearance types

The "D" in D6 refers specifically to Department of Defense clearances. Other federal agencies issue their own clearances. The Department of Energy issues Q and L clearances (for access to nuclear information). The State Department issues clearances for diplomatic work. The FBI and CIA issue their own clearances. While the investigation process is similar across agencies, the specific requirements and access levels differ.

Within the Department of Defense system, you may also encounter the term "TS/SCI" (Top Secret/Sensitive Compartmented Information), which is a higher level than D6 and requires a polygraph. You might also see "Confidential" or "Secret" used without the "D" prefix, particularly in older documents or in military contexts. The terminology can be confusing, but the key point is that a D6 is a DoD Secret clearance, and it sits in the middle of the three-tier system.

Frequently Asked Questions

Can I get a D6 clearance on my own, or does my employer have to request it?

Your employer must request it. You cannot initiate a clearance on your own. The employer submits the request through their facility security officer, and the clearance is granted to you in connection with that specific job. If you are job hunting and want to work in a cleared position, you can mention your interest in cleared work, but the clearance itself is requested only after you are hired.

What happens if I lie on the SF-86 form?

Lying on the SF-86 is a federal crime. Even if the lie is discovered years later, you can be prosecuted for making false statements to the government. Investigators often uncover inconsistencies during interviews, and if they find that you deliberately omitted or falsified information, your clearance will be denied and you may face criminal charges. If you are unsure how to answer a question, it is better to disclose the uncertainty or seek guidance from your security officer than to guess or hide information.

How much does a D6 clearance cost me personally?

There is no cost to you. Your employer pays for the investigation and processing. You are not billed for the background check, interviews, or clearance issuance. The only cost to you is your time — completing the SF-86 thoroughly and accurately, and participating in interviews with investigators.

Can I transfer my D6 clearance to a different employer?

Your clearance is not transferable in the sense that you cannot take it with you like a credential. However, if you move to a new job that also requires a Secret clearance, your new employer can request that your existing clearance be transferred or reinstated. This is faster than a new investigation because the background work is already done. The new employer's security officer handles the paperwork.

What should I do if my life circumstances change after I get my clearance?

You are required to report significant changes to your security officer — a criminal arrest, a major debt or financial problem, a foreign contact, a move abroad, or a change in substance use. Reporting these changes voluntarily, rather than waiting for an investigator to discover them, shows integrity and usually results in a better outcome than if the information surfaces during a reinvestigation.