RV Water Tank Guide for Campers and Travel Trailers

RV water systems aren’t complicated, but they punish neglect. A tank that isn’t sanitized grows bacteria. A filter that isn’t changed lets sediment wreck your faucets. Gray water left sitting for a week smells like a swamp.

This guide covers everything — tank sizes, sanitizing, gray and black water management, filtration, faucet replacement and campground hookup.

RV Water Tank Sizes by Type

Every RV has at least two tanks. Most have three.

Fresh Water Tank

Holds clean water for drinking, cooking, dishes and showers.

RV Type	Fresh Water Capacity	Days Without Hookup (2 people)
Teardrop / Small	10-20 gal	1-2 days
Pop-Up	15-30 gal	1-3 days
Single-Axle Travel Trailer	30-45 gal	2-3 days
Dual-Axle Travel Trailer	40-60 gal	3-4 days
Large Travel Trailer	50-80 gal	4-6 days
5th Wheel	60-100 gal	5-7 days
Class C Motorhome	35-60 gal	3-5 days
Class A Motorhome	75-150 gal	5-10 days

Water weighs 8.34 lbs per gallon. A full 60-gallon tank adds 500 lbs to your trailer. That’s real weight — factor it into your towing calculations. Many experienced campers tow with tanks half full and fill up at camp.

Gray Water Tank

Collects wastewater from sinks and the shower. Usually sized at 60-80% of the fresh water tank. A trailer with a 50-gallon fresh tank typically has a 30-40 gallon gray tank.

Gray water fills faster than you’d expect. Long showers and doing dishes without conserving can fill a 35-gallon gray tank in two days.

Black Water Tank

Collects toilet waste. Usually 25-40 gallons. Smaller than the gray tank because toilet flushes use less water than showers and sinks.

A 30-gallon black tank lasts 4-6 days for two people at normal use. Use plenty of water with each flush — dry flushing leads to pyramid buildup that’s miserable to deal with later.

How to Sanitize Your RV Fresh Water Tank

Do this every spring before your first trip and after any storage period longer than two weeks. Bacteria, mold and algae grow in stagnant water tanks — even in ones that look clean.

What You Need

• Household bleach (unscented, 5-6% sodium hypochlorite)
• Measuring cup
• Funnel (if your gravity fill is small)
• Fresh water hose

Sanitizing Steps

Step 1: Drain the fresh water tank completely. Open the low-point drain valves and let everything empty.

Step 2: Calculate your bleach amount. Use 1/4 cup of bleach per 15 gallons of tank capacity. A 45-gallon tank needs 3/4 cup. A 60-gallon tank needs 1 cup.

Step 3: Mix the bleach with a gallon of water in a container. Pour it into the fresh water tank through the gravity fill.

Step 4: Fill the tank completely with fresh water.

Step 5: Turn on the water pump. Open every faucet (hot and cold) one at a time until you smell bleach. This pulls the bleach solution through every line in the system — kitchen, bathroom, shower and outdoor shower if you have one.

Step 6: Let it sit for 4-12 hours. Overnight is ideal.

Step 7: Drain everything. Open all drains and let the tank empty.

Step 8: Refill with fresh water. Run every faucet until the bleach smell is gone. If it still smells after one rinse, drain and refill again.

How to Sanitize the Water Lines

The tank is only half the job. Bacteria can live in the lines too.

After sanitizing the tank (steps above), the bleach solution has already run through the lines. But if your lines have biofilm buildup (slimy residue inside the tubing), a standard bleach flush might not cut it.

For stubborn biofilm, use an RV water system cleaner like Camco TastePURE Spring Fresh. It’s designed to break down organic buildup in lines and tanks. Follow the product instructions — most require filling the system, letting it sit and flushing twice.

Gray Water Tank Management

Gray water isn’t sewage, but it’s not clean either. Food particles from the kitchen sink, soap residue, hair and skin cells accumulate and create odors fast — especially in Texas heat.

Preventing Gray Tank Odors

Don’t let it sit. Dump gray water every 2-3 days in hot weather. Bacteria multiply fast above 80°F.

Use enzyme treatments. Drop a gray tank treatment pod (like Happy Campers or Unique RV) in after each dump. Enzymes break down organic matter before it can stink.

Screen your drains. Mesh drain screens in the kitchen and bathroom sinks catch food particles and hair that cause clogs and odors in the tank.

Flush the tank. When dumping, dump the gray tank last so soapy water rinses the dump hose. If your RV has a gray tank flush port, use it to rinse the tank interior.

RV Water Filtration and Purification

Campground water quality varies wildly. One park has crystal clear municipal water. The next has well water that smells like sulfur and tastes like a swimming pool.

Inline Carbon Filters

The most common solution. A basic inline filter connects between the campground spigot and your city water inlet. It removes chlorine, sediment and bad taste.

Popular models: Camco TastePURE, Culligan RV-800. These cost $15-25 and last 3-6 months depending on water quality. Replace them when flow rate drops noticeably.

Two-Stage Filter Systems

A sediment pre-filter (5 micron) catches sand, rust and particulates before they reach the carbon filter. This extends the carbon filter’s life and protects your plumbing.

Canister systems like the Clearsource or Hydro Life mount on the side of the trailer or sit on the ground at the hookup. They filter more effectively than single inline units and last longer between changes.

UV and Multi-Stage Purification

For boondocking or questionable water sources, a UV purifier kills bacteria and viruses that carbon filters miss. These mount under the sink and treat water as it flows to the faucet.

Multi-stage systems combine sediment filtration, carbon block and UV treatment. Overkill for campground water — but worth it if you fill from rivers, springs or remote well pumps.

Water Pressure Regulators

Not a filter, but just as important. Campground water pressure ranges from 20 PSI (barely a trickle) to 100+ PSI (enough to blow a fitting). RV plumbing is rated for 40-60 PSI.

Use an adjustable water pressure regulator at the spigot. Set it to 45 PSI. A $15 brass regulator prevents hundreds of dollars in blown fittings and water damage.

RV Faucet Replacement

RV faucets are lightweight plastic or chromed pot metal. They wear out faster than residential faucets — handles get loose, cartridges leak and finishes flake off after 3-5 years.

When to Replace vs Repair

Replace if: The base is corroded, the spout wobbles at the mount, the finish is peeling or the cartridge isn’t available.

Repair if: Just the cartridge drips. Most RV faucets use standard cartridges that cost $5-15.

Replacement Steps

1. Turn off the water pump and open a faucet to relieve system pressure
2. Disconnect supply lines under the sink — usually 1/2-inch PEX with push-fit or compression fittings. Have a towel ready for residual water
3. Remove mounting nuts — two nuts under the sink hold the faucet to the counter
4. Lift out the old faucet and clean the mounting surface
5. Drop in the new faucet — make sure the gasket seats flat against the counter
6. Hand-tighten mounting nuts — don’t overtighten or you’ll crack the counter
7. Reconnect supply lines — push-fit connections click when seated. Compression fittings need a wrench but don’t gorilla them
8. Turn on the pump and check every connection for drips

Choosing an RV Faucet

RV faucets use standard 3-hole spacing (4 inches center to center for most kitchen faucets). You can install residential faucets if the hole spacing matches, but residential units are heavier and may need support underneath.

Stick with brands that make RV-specific faucets — Dura Faucet, Phoenix, Empire. They’re designed for the lighter counters and thinner supply lines in campers.

Campground Water Hookup

What You Need

• Drinking-water-safe hose — white or blue, not a green garden hose. Garden hoses leach chemicals that taste terrible and may not be food-safe
• Inline water filter — connects between spigot and hose
• Pressure regulator — set to 40-50 PSI
• 90-degree elbow (optional but recommended — reduces stress on the city water inlet)

Hookup Steps

1. Connect the pressure regulator to the campground spigot
2. Connect the inline filter to the regulator
3. Connect your drinking water hose to the filter
4. Connect the other end of the hose to your RV’s city water inlet (the one labeled “City Water” — not the gravity fill)
5. Turn on the spigot slowly — check for leaks at every connection
6. Open a faucet inside the RV to confirm water flows

The city water inlet bypasses your onboard pump and tank. Water flows directly from the campground supply to your faucets at whatever pressure the regulator allows.

Filling the Fresh Water Tank

If you want to fill the onboard tank instead (for dry camping later), connect the hose to the gravity fill port. This is a separate inlet — usually a screw cap on the side of the trailer. Run the hose until water overflows from the tank vent. Cap it and you’re set.

Water Hookup at Home

Same setup. Connect a drinking-water-safe hose from an outdoor spigot to your city water inlet. Add the filter and regulator. This is how most people clean, flush and test their RV plumbing between trips without draining the onboard tank.

If you’re doing extended home hookup (living in the driveway during renovations, for example), use a heated hose in winter. Standard hoses freeze and burst below 32°F.

Where to Fill Your RV Water Tank

When boondocking or traveling between campgrounds:

• Campground dump stations — most have a fresh water fill spigot near the dump
• Rest areas — some state rest areas have potable water spigots
• Gas stations — ask at truck stops. Many have a potable water fill area
• RV dealerships — some let you fill if you ask
• National forest and BLM land — developed campgrounds usually have water. Dispersed sites don’t
• Walmart parking lots — some have outdoor spigots available (ask the manager)

The FreshWaterFinder app and iOverlander app both map potable water fill stations across the country.

Related Guides

• How to Winterize a Camper
• RV Black Tank Flush
• RV Water Pump Not Working
• RV Water Heater Bypass
• RV Toilet Seal Replacement