How to Sanitize Your RV Water Tank After Summer Storage - Complete Guide to Cleaning and Maintaining Fresh Water Systems

The Rundown

Given that your Navion has been sitting empty since early August here in Arizona heat, you should definitely sanitize the water system before using it next week. While you drained the tanks properly, the combination of residual moisture, desert dust infiltration, and the extreme Arizona temperatures creates ideal conditions for bacterial growth in your water lines and tank. A simple rinse won't eliminate potential contaminants that may have developed over these months of storage. Sanitizing is the safe play for first-time full-timers making this transition from seasonal to year-round RV living.

The good news is this is absolutely a routine maintenance task that every RV owner should know. Since you properly drained before storage, you've already done the hard part right. Now it's just about ensuring your water system is safe and fresh for your return to RV life after the Arizona summer break.

Why It Happens

Extended empty storage periods create several conditions that make sanitization necessary. Even though you drained the tanks, small amounts of water always remain in low points of the plumbing system, especially in the water heater and pump areas. Over several months, this stagnant water becomes a breeding ground for bacteria and can develop unpleasant tastes and odors.

Arizona's extreme summer heat compounds the problem by creating thermal cycling in your RV's plumbing. As temperatures soar above 110°F during the day and drop at night, this expansion and contraction can draw dust and airborne contaminants into the system through small gaps or the tank vent. The desert environment introduces fine particles that can settle in your water system.

Additionally, rubber seals and gaskets in your water system can dry out during extended storage, potentially allowing contamination entry points. The Navion's fresh water system, like most Class B+ motorhomes, has multiple connection points and a relatively complex plumbing layout that makes thorough flushing essential after storage periods.

Gather These Items

• Unscented liquid chlorine bleach (sodium hypochlorite) - small bottle sufficient
• Potable water hose (white/blue RV-safe hose, not a garden hose)
• Water pressure regulator
• Funnel for adding bleach to tank
• Clean measuring cup (1/4 cup capacity)
• Non-metallic tank cleaning wand or long-handled brush (optional, for heavily soiled tanks)
• Fresh water source connection
• Rubber gloves for handling bleach solution

The Fix

Start by preparing a chlorine solution using 1/4 cup (4 tablespoons) of unscented bleach for every 15 gallons of fresh water tank capacity. For most Navion models with a typical 21-gallon fresh water tank, use approximately 5.5 tablespoons of bleach. Mix this solution thoroughly in a clean container before adding it to your tank.

Add your measured bleach solution directly to the empty tank through the gravity fill or using a funnel at the tank inlet, then fill the tank completely with fresh water while the filling action helps mix and distribute the bleach solution throughout the tank. This creates the proper sanitization concentration for RV water systems.

Ensure your water heater is turned off before beginning. Turn on your water pump and systematically open each faucet, starting with cold water taps, then hot water, until you smell chlorine coming from each fixture. Don't forget the shower, toilet if it uses fresh water, and any exterior wash stations. Let each run until the chlorine smell is strong, then close the faucets. This process ensures the sanitizing solution reaches every part of your water system.

Allow the solution to sit in the system for at least 4 hours, though overnight is better for maximum sanitization. After the contact time, drain the entire system by opening all faucets and draining the fresh water tank completely. Refill with clean water and flush the system multiple times until there's no chlorine smell or taste remaining in any of the fixtures.

Know Your Limits

This sanitization process is well within the capabilities of any RV owner and should take about 30 minutes of active work plus waiting time. However, if you discover any unusual tastes, odors, or discoloration that persists after multiple flushes, you may need professional inspection of your water system components.

If your Navion has been sitting in extreme temperatures for extended periods, consider having the water heater professionally serviced as well, especially if it's been more than a year since the last service. The anode rod may need replacement, and mineral deposits could have accumulated during the storage period.

Watch for any leaks during the refill process, as rubber seals may have dried and cracked during storage. Small leaks at fittings can often be addressed with gentle retightening, but major leaks or pump issues require professional attention. Since you're transitioning to full-time Arizona living, establishing a relationship with a local RV service center for more complex repairs is wise.