Charmin offers a variety of toilet paper options, but not all are septic-safe. Charmin Essentials Soft and Charmin Ultra Soft are both septic-safe and designed to break down quickly in septic tanks.  However, Charmin Ultra Strong and Charmin Ultra Gentle are not certified as septic-safe and may not break down as easily in septic systems. Check the packaging or the manufacturer's website to be sure is it.