Most RVers assume all freshwater tanks are basically the same, but tank location dramatically affects water quality in ways that become obvious only after you’ve owned your rig for a while. Tanks mounted underneath the RV, especially those positioned near the engine or exhaust systems, can develop persistent taste and odor problems that no amount of sanitizing seems to fix.
The issue isn’t contamination — it’s heat cycling. Freshwater tanks located under the rig or in heated compartments experience constant temperature changes that accelerate the breakdown of plastic compounds in the tank walls. This creates the musty or chemical taste that many owners blame on campground water or old hoses. Interior-mounted tanks or those in well-ventilated compartments away from heat sources tend to maintain better water quality long-term.
You can’t change your tank’s location after purchase, but understanding this helps explain why some RVs develop water taste issues within the first year while others stay fresh for years. If you’re shopping for an RV, ask where the freshwater tank is mounted and whether it’s insulated from heat sources. If you already own a rig with a problematic location, upgrading to a better water filtration system becomes more important than for owners with better tank placement.
This is also why experienced RVers often recommend carrying drinking water separately for rigs with underneath tank mounting, especially in hot climates where the problem accelerates.