Purple tablets are not required in primary containment facilities under standard building codes or health regulations
Purple tablets—also called purple potassium permanganate tablets or purple oxidizing tablets—serve a specific purpose in water treatment and odor control, but they are not a mandatory component of primary containment systems. Whether you need them depends entirely on what you are storing, what problems you are trying to prevent, and your local environmental or health department rules. A primary containment facility that holds clean water, for example, has no use for them. A facility storing chemicals that produce hydrogen sulfide gas or that need oxidation treatment may benefit from them, but that is a choice based on your situation, not a requirement.
Building code requires your containment structure itself—the volume, material, and integrity of the walls and floor. It does not require you to add chemical treatments inside that structure. Those treatments are tools you choose based on what you store and what your local agency says you need for that specific material.
Key Takeaways
- Purple tablets are optional additions to primary containment, not mandatory equipment under building code.
- They are most useful when you are storing materials that produce odors, gases, or need chemical oxidation.
- Your local environmental agency or health department can tell you whether your specific storage situation calls for them.
- If you do use purple tablets, they must be stored safely inside the containment and replaced on a schedule that matches your facility's needs.
- Confusing purple tablets with required containment equipment can lead to unnecessary cost or, conversely, missing a control measure you actually do need.
What purple tablets actually do in containment
Purple potassium permanganate tablets work by releasing permanganate ions into liquid or air. In water, they oxidize dissolved compounds—particularly hydrogen sulfide, which produces the rotten-egg smell common in some storage tanks and sumps. In air or vapor spaces, they can help neutralize certain odorous gases. The purple color is straightforward the visual indicator that the permanganate is present and active.
They are not a structural part of your containment system. They do not strengthen the walls, floor, or liner. They do not meet any containment volume requirement. They are a chemical tool you add inside the containment to manage a specific problem—odor, corrosion from hydrogen sulfide, or oxidation of certain stored materials. Think of them as a treatment you explore to the contents, not as part of the container itself.
When your facility might need them
Purple tablets become useful in a few common scenarios. If you store wastewater, septic effluent, or materials that decompose and produce hydrogen sulfide, the smell can become a serious issue for neighbors and staff. If your containment holds rainwater runoff that sits for weeks, stagnation and odor develop. If you store certain industrial chemicals or process water that needs oxidation as part of treatment, permanganate tablets can be part of that process.
They are also sometimes used in facilities that hold materials prone to corrosion from acidic or sulfide-rich environments. The permanganate can help neutralize some of those compounds before they damage the containment structure itself. However, if your primary containment holds clean water, new oil, or materials that do not produce gases or odors, you have no reason to use them. Adding them would be unnecessary cost and maintenance.
How to know if your situation requires them
The best source of information is your local environmental protection agency, health department, or the agency that oversees hazardous materials storage in your area. They can review what you are storing and tell you whether odor control, oxidation, or gas management is required by regulation in your jurisdiction. Many agencies have written guidance specific to the materials you store, and some have staff who can answer questions by phone.
You should also check any permits or compliance documents you received when your containment facility was approved. Some permits specifically require or prohibit certain additives. If your facility is part of a larger industrial operation, your environmental compliance officer or facility manager will know whether permanganate treatment is part of your approved process. If you are experiencing odor problems or noticing corrosion inside your containment, that is a sign you may need them—but before you add anything, contact your local agency to confirm it is allowed and appropriate for your specific materials.
Storage and safety if you do use purple tablets
Purple permanganate tablets must be stored inside the primary containment itself, not outside it. They are oxidizing agents and can react with certain materials, so keep them away from organic matter, acids, and reducing agents. Store them in a dry location within the containment, in a sealed container if possible, to prevent premature dissolution and to keep them organized.
Replace them on a schedule that matches your facility's needs—typically every few months to a year, depending on how much liquid is in the containment and how quickly the permanganate is consumed. Check the tablets regularly to see if they are still purple; if they have turned brown or colorless, they are no longer active and should be replaced. Keep a log of when you add and replace them so you can track whether the schedule is working for your situation.
Common confusion about purple tablets and containment rules
Some facility managers assume purple tablets are required because they see them mentioned in industry guides or because a neighboring facility uses them. Others think they are optional and skip them even when their local rules call for odor control. The confusion usually comes from mixing up what is required by code (the containment structure itself) with what is required by your specific situation (the tools you use inside it).
Your primary containment must meet volume, material, and structural standards set by building code and environmental law. Whether you add purple tablets, carbon filters, aeration, or other treatment tools depends on what you are storing and what your local agency says you need. Do not assume one facility's setup applies to yours. What works for a wastewater station may be wrong for an oil storage tank, and vice versa.
When to call a professional or contact your agency
If you are unsure whether your facility needs purple tablets, contact your local environmental protection agency or health department before making changes. If you are experiencing odor, corrosion, or other problems inside your containment, have a professional inspect it before adding anything. If your containment is aging or showing signs of wear, that is a structural issue that requires repair, not a chemical fix.
Do not assume that adding purple tablets solves a containment problem. They manage odor and some chemical reactions, but they do not repair a leaking containment, increase its volume, or meet structural requirements. If your containment is failing, that is a separate issue that requires repair or replacement by a may have access to contractor.
Frequently Asked Questions
Are purple tablets required by law in primary containment?
No. Building code and environmental law require the containment structure itself—volume, material, and integrity. Purple tablets are optional tools you add inside containment if your specific situation calls for odor control or chemical oxidation. Your local agency can tell you whether your facility needs them.
Can I use purple tablets instead of fixing a leaking containment?
No. Purple tablets manage odor and some chemical reactions, but they do not repair structural damage or increase containment volume. A leaking containment must be repaired or replaced. Tablets are a supplement to a working containment, not a substitute for one.
How often do purple tablets need to be replaced?
Replacement depends on how much liquid is in your containment and how quickly the permanganate is consumed. Most facilities replace them every three to twelve months. Check them regularly—when they turn brown or colorless, they are no longer active and should be swapped out.
What happens if I store purple tablets outside the containment?
They must be stored inside the primary containment to be effective and to comply with most regulations. Storing them outside defeats their purpose and may violate your facility's permit. Keep them in a sealed, dry location within the containment itself.
Do purple tablets work on all types of odors?
No. They work best on hydrogen sulfide and certain other gases produced by decomposition or chemical reactions. They are less effective on odors from volatile organic compounds or other sources. If you are not sure what is causing the smell, have the liquid tested before adding tablets.