5 DEF Storage Tips for Your Onsite Diesel Exhaust Fluid Supply

DEF storage tips

In the trucking world, environmental regulations have become increasingly stringent, driving the need for advanced emission reduction systems. Enter diesel exhaust fluid (DEF), a vital component that ensures trucks comply with these standards while optimizing performance. If you're managing an onsite DEF supply, you understand the importance of preserving its integrity over time. To help you navigate the complexities of DEF storage, we've compiled three essential tips that will maintain the quality of your DEF and contribute to smoother operations and greener transportation. So, let's dive in and explore the best practices for storing DEF on your premises.

1. Store DEF at the Right Temperature:

The temperature at which you store DEF can significantly impact its shelf life. It is recommended to keep DEF within a temperature range of 12°F to 86°F (-11°C to 30°C). Extreme temperatures can compromise the quality of your DEF supply. Freezing temperatures cause DEF to solidify, requiring complete thawing before use. On the other hand, high temperatures contribute to ammonia formation, which reduces DEF quality and can negatively affect vehicle performance. To maximize shelf life, storing DEF at temperatures below 65°F (18°C) is best.

2. Store DEF Away From Direct Sunlight:

The location of your onsite DEF storage tank plays a vital role in maintaining DEF quality. Direct sunlight can lead to evaporation of the water content in DEF, altering the urea concentration and reducing its effectiveness. Place your DEF storage tanks in shielded areas away from direct sunlight to prevent evaporation. Consider shaded or indoor spaces that minimize exposure to sunlight. Protecting your DEF supply from evaporation ensures its usability and effectiveness over an extended period.

3. Use a Closed-Loop DEF Transfer System:

Contamination can severely impact the quality of your DEF supply. Even small amounts of impurities such as phosphorus, magnesium, calcium, sodium, or potassium can compromise the entire contents of your DEF storage tank. To prevent contamination, a closed-loop DEF transfer system is recommended. This system allows you to move DEF from your onsite storage tank to the holding tanks on your trucks without exposing it to outside contaminants. Remember to keep the area around each truck's DEF tank opening clean to avoid introducing contaminants during the transfer process. A closed-loop transfer system minimizes the risk of engine shutdowns, selective catalytic reduction system malfunctions, and other engine damage caused by contaminated DEF.

4. Avoid Cross-Contamination:

Cross-contamination can severely compromise the quality and effectiveness of your onsite diesel exhaust fluid (DEF) supply. It is crucial to store DEF separately from other substances, especially petroleum-based products such as diesel fuel or oil. Cross-contamination can occur when DEF comes into contact with even small traces of these substances, leading to chemical reactions and a decline in DEF quality.

To prevent cross-contamination, ensure that DEF storage tanks, equipment, and dispensing systems are labeled and dedicated exclusively to DEF. Separate DEF storage areas from areas used for other fluids, and take precautions to avoid accidental spills or mix-ups. By maintaining strict segregation practices, you can protect the integrity of your DEF supply, ensuring that it remains pure and effective for your vehicles' SCR systems.

Remember, DEF is a specialized fluid with specific requirements, and keeping it separate from other substances is essential for maximizing its performance and ensuring compliance with emission standards.

5. Protect DEF from Contaminants:

To maintain the quality and effectiveness of your onsite diesel exhaust fluid (DEF) supply, it is crucial to protect it from contaminants. DEF is highly sensitive to impurities; even small amounts of certain substances can jeopardize its integrity. Here are some key measures to safeguard your DEF from contaminants:

a. Use Sealed Containers: When storing DEF, use sealed containers that prevent the entry of dust, dirt, and airborne particles. This helps maintain the fluid's purity and minimizes the contamination risk.

b. Secure Storage Tanks: Ensure your DEF storage tanks are securely closed and properly sealed. This prevents the intrusion of foreign substances that can compromise the quality of your DEF supply.

c. Prevent Spills and Leaks: Implement robust spill prevention measures to avoid accidental spills or leaks that can introduce contaminants into your DEF storage area. Adequate containment systems, such as spill trays or secondary containment, can help contain any potential spills and protect against environmental contamination.

d. Practice Good Housekeeping: Maintain a clean and organized storage area for your DEF. Regularly clean the storage tanks, equipment, and surrounding areas to remove potential contaminants. Proper housekeeping practices minimize the risk of contamination and ensure the longevity of your DEF supply.

e. Handle DEF with Care: When handling DEF, use dedicated equipment, such as clean funnels or pumps, to avoid cross-contamination. Avoid using funnels or containers in contact with other fluids or substances.

By implementing these protective measures, you can significantly reduce the risk of contamination and preserve the quality of your onsite DEF supply. A clean and uncontaminated DEF supply ensures optimal performance of SCR systems, lowers the risk of engine malfunctions, and helps you meet emissions standards effectively.


Proper storage techniques are essential to maintaining the quality and effectiveness of your on-site DEF supply while meeting EPA standards. By storing DEF at the appropriate temperature range, protecting it from direct sunlight, and utilizing a closed-loop transfer system, you can ensure that your trucks can access high-quality DEF at all times. For more information on on-site DEF delivery and storage, please get in touch with us. Safeguard your DEF supply and contribute to cleaner emissions and optimal vehicle performance.