Why Your RV’s Fresh Water Tank Tastes Bad & How to Fix It

Jordan Concannon
Apr 15
4 min read

Clean, fresh-tasting water is essential when you're living or traveling in an RV. But if you've ever taken a sip and noticed a weird taste—like plastic, metal, sulfur, or mildew—you know it can ruin your whole day.

That unpleasant flavor is more than just a nuisance. It might signal a problem in your water system that needs attention. In this post, we’ll break down the most common causes of bad-tasting RV water, how to fix them, and tips to keep your fresh water tank clean and safe.

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Stale Water in the Tank
Plastic Taste from New or Unused Tanks
Contaminated Freshwater Hose
Sediment Buildup in the Fresh Water Tank
Neglected Water Filters
Source Water Quality

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🚰 1. Stale Water in the Tank

Why it tastes bad: Water that sits still for an extended period—especially in hot weather—becomes a breeding ground for bacteria, biofilm, and other organic contaminants. Over time, these microorganisms begin to grow on the inside walls of your freshwater tank and hoses, giving the water a musty, sour, or slightly moldy flavor. If the water smells or tastes earthy or “off,” this is often the culprit. Sediment and minerals may also settle at the bottom of the tank, worsening the problem.

How to fix it:

Drain your entire freshwater tank through the low point drain and faucets
Mix 1/4 cup of regular household bleach per 15 gallons of tank capacity with water, pour into the tank
Fill the tank with water, run the solution through all faucets and fixtures
Let sit for 4–8 hours, then flush with fresh water until the bleach smell is gone

Pro Tip: Keep a tank sanitizer or oxygen-based cleaner on hand for a gentler, bleach-free option if you’re sensitive to chlorine.

☕ 2. Plastic Taste from New or Unused Tanks

Why it tastes bad: New RVs, replacement tanks, or RVs that haven’t been used for a while often have a strong plastic or chemical taste. This comes from residual compounds like polyethylene and plasticizers used during the tank’s manufacturing process. These compounds leach into the water and become more noticeable when water sits in the system, especially in warmer temperatures or if you use hot water.

How to fix it:

Fill the tank with a solution of water and baking soda (1/2 cup per 15 gallons), or vinegar (1 cup per 10 gallons—not both)
Let it sit for 24 hours, then drain and flush thoroughly
Repeat until taste is gone

Pro Tip: Run the treated water through every fixture—kitchen sink, bathroom faucet, outdoor shower, and especially the water heater—to completely purge the system.

🍋 3. Contaminated Freshwater Hose

Why it tastes bad: Your water hose is your RV’s main water supply line—and if it’s not rated for potable water use, or it’s old, left in the sun, or improperly stored, it can become a major source of contamination. Bacteria, algae, and mold love the damp, dark inside of hoses, especially when not fully drained after use. Even high-heat exposure can break down the hose lining and release plastic or rubber taste into your water.

How to fix it:

Replace hoses annually or if you notice discoloration, cracking, or smell
Only use hoses labeled “drinking water safe” (typically white or blue)
Flush your hose for 15–30 seconds before each use

Pro Tip: Store your hose with both ends connected or capped to keep debris and insects out. A hose bag helps protect it from UV damage.

🚙 4. Sediment Buildup in the Fresh Water Tank

Why it tastes bad: Over time, tiny particles from campground water—rust, sand, silt, and other minerals—settle in your tank and accumulate along the bottom or in corners. This sediment can host bacteria, discolor the water, clog your water pump screen, and contribute to a gritty or metallic taste. Once stirred up while driving, it can move through your plumbing system and reduce water quality in all fixtures.

How to fix it:

Install a sediment pre-filter at your city water connection
Flush the tank completely every few weeks, especially after filling from unfamiliar sources
Use a tank wand or spray nozzle to break up sediment buildup inside the tank

Pro Tip: Add a strainer to your water pump intake line to catch any loose debris before it enters the system.

🔌 5. Neglected Water Filters

Why it tastes bad: Water filters are great—until they’re not. When filters get clogged, expired, or overused, they not only stop filtering effectively but may start harboring bacteria or mold. A carbon filter that’s past its prime can cause sour, metallic, or “stale” tasting water. Some filters even release black carbon dust into the lines.

How to fix it:

Replace inline filters every 3–6 months (more frequently in full-time use or poor water conditions)
Clean and sanitize filter housings during filter swaps
Consider upgrading to a multi-stage or under-sink filtration system for drinking water

Pro Tip: Keep extra filters on board so you're never caught with a bad taste and no replacement on hand.

🚿 6. Source Water Quality

Why it tastes bad: Even if your RV water system is clean, the source water itself may not be. Campground water can range from treated city water (often heavy in chlorine) to unfiltered well water (which can contain iron, sulfur, or high mineral content). These minerals and additives often lead to strong metallic, earthy, or chemical tastes.

How to fix it:

Always use a carbon-based inline water filter at the spigot
When possible, fill tanks at filtered water stations or RV parks with good reviews
Avoid filling at dump stations, gas stations, or unverified hoses

Pro Tip: Keep a TDS (total dissolved solids) meter on hand to test water before filling—it’s quick, cheap, and helps you spot poor quality sources fast.

📦 Final Thoughts...

If your RV’s fresh water tastes bad, don’t ignore it. The taste is often your first sign of deeper maintenance issues, contamination, or component wear. Keeping your water system clean isn’t just about taste—it’s about protecting your health and your rig.

With regular cleaning, smart filtration, and careful sourcing, you can enjoy clean, great-tasting water wherever the road takes you.

Want help diagnosing your water system or upgrading your filtration setup? We’ve got your back.

Until next time,

Jordan @ Rolling Rabbit RV Repair

"Keeping you rolling, wherever the road takes you."