this is copied and hilighted from the links above
Sellers are already required to disclose hazardous substances and environmental concerns in their seller disclosure statements, so they would need to disclose meth production based on those issues. As a real estate licensee, if you are aware that a property was used in the manufacturing of meth, or you have a reasonable basis to suspect that it was and the seller hasn’t disclosed that information, you need to disclose that condition to the buyer. Buyer and seller agents who fail to disclose material defects they have “actual” knowledge of can be held liable under the Real Estate Seller Disclosure Law.