Mobile RV Fresh Water Tank Repair and Service Across Florida
A cracked or leaking fresh water tank is discovered in stages - first a mysterious drop in water level, then a wet floor, then a problem that has been growing for weeks. Tank repair is always cheaper than the downstream damage that follows it.
Most RV fresh water tanks are rotationally molded polyethylene - a material that handles pressure and flex well but is genuinely damaged by prolonged UV exposure through open access panels and by stress cracking at fitting bosses when overtightened during installation. The first crack in a Florida coach is usually not at the tank wall itself but at the fitting threads, where the plastic has thinned and where the installer applied a wrench with too much torque.
Distinguishing a Tank Leak from a Supply Line Leak
A dropping water level in the fresh tank can mean a leaking tank or a leaking supply line, and telling them apart without a pressure test wastes time. Jesse's method is to isolate the tank by closing the outlet and the fill port, then pressurize the tank side alone with a hand pump to 5 PSI - far below operating pressure but enough to surface any active leak at a fitting or a crack. If the tank holds, the problem is downstream in the supply lines.
Visual inspection helps narrow the search before the pressure test. A wet floor under the tank compartment with no damp cabinet interiors points to the tank or its fittings. Wet under a cabinet with a dry tank compartment points to a supply line joint at a fixture. In a coach that has been sitting, mineral staining or a white residue around a fitting is often the clearest tell.
Can a Polyethylene Tank Be Repaired?
Polyethylene welding is viable for cracks that run along the tank body and have not penetrated all the way through the attachment bosses. The repair involves grinding a V-groove along the crack, heating the tank wall and a PE filler rod simultaneously, and flowing the filler into the groove under pressure from a welding shoe. Done correctly, the weld matches the parent material strength within about 80 percent.
Fitting boss cracks are a different problem. The boss is the thickened pad where a threaded fitting screws in, and the crack almost always starts at the root of the threads. Welding around threads produces inconsistent results because the threaded area has already thinned below spec. In these cases, a new fitting boss needs to be bonded on or the tank replaced. Jesse photographs the damage before making a recommendation and will not charge for a repair that is unlikely to hold.
Why Florida Heat Cracks Fresh Tanks
Polyethylene expands and contracts with temperature, and Florida's daily temperature swings - from a 68-degree night to a 95-degree afternoon - create repeated thermal cycling at every fitting boss. Over years, this work-hardens the plastic around threaded fittings and promotes stress cracking. Coaches parked in direct sun with the underbelly access panel removed accelerate this process by allowing UV to degrade the tank surface directly.
High chlorine in municipal water supplies - common in coastal Florida cities - also plays a role. Chlorine attacks polyethylene slowly, reducing its flexibility and making existing stress cracks propagate faster. Tanks in coaches that fill exclusively from treated municipal sources age faster than those using well water or filtered campground supplies.
Sanitizing a Fresh Tank After Florida Storage
A fresh tank left partially full through a Florida summer is a reliable incubator for biofilm and bacterial colonies. The warm, still water - often 85-90 degrees inside an enclosed underbelly - produces conditions that a 15-minute bleach treatment barely addresses. The correct protocol is a 100 parts per million chlorine solution held in the tank for four hours, followed by a complete flush and a re-fill test for taste and odor.
Jesse mixes the sanitizing solution fresh on each call using household bleach and confirms the concentration before adding it to the tank. After the hold period, the entire system - including the water heater bypass, all supply lines, and the pump - is flushed until chlorine odor is undetectable. A tank that still smells after two flushes has biofilm embedded in fittings or the pump strainer, which requires disassembly.
Filling a Tank That Has Been Dry
An empty polyethylene tank that has sat dry for months can develop a faint plasticky odor when first filled, particularly if it has been stored in heat. The first fill should be run to drain and repeated once before the water is used for anything other than flushing. This purges any off-gassing and confirms that no dust, insects, or sediment have entered through an open vent.
Filling too quickly through the gravity port can also cause momentary pressure buildup if the vent is blocked by a mud dauber nest - another Florida-specific issue in summer storage. Slow filling through the gravity port and listening for vent airflow is the correct technique, particularly for a tank coming out of extended storage.
Odors That Persist After Tank Service
Water that smells odd after a fresh tank repair or sanitization is almost always the pump strainer or the water heater anode, not the tank. The strainer accumulates biofilm and acts as a re-inoculation point even after the tank has been treated. Removing, cleaning, and if necessary replacing the strainer is part of every fresh tank service call.
The anode rod in the water heater is the other culprit. A depleted anode generates hydrogen sulfide in hot water, producing the sulfur odor that owners associate with a tank problem. Cold water smells fine; hot water smells like eggs - that pattern points to the anode, and the fix is a new rod and a heater flush, not further tank work.
Service Pricing
| Service | Notes | Typical Range |
|---|---|---|
| Service call + leak trace | Includes pressure test of tank and supply lines; isolates the source | $299 - $399 |
| Fresh tank fitting / vent replacement | Gravity fill port, vent, or level sender | $95 - $240 |
| Tank crack repair (polyethylene weld) | Small cracks; not all locations repairable - assessed on inspection | $150 - $380 |
| Full tank replacement | Tank only; installation complexity varies by coach | $350 - $950 |
| Sanitization (bleach + flush cycle) | Post-storage or post-repair; 100 ppm treatment and full flush | $95 - $185 |
Pricing transparency: All prices are estimates based on typical coach configurations. Labor-intensive access situations, custom coach layouts, and parts availability affect the final figure. The service call fee of $299 - $399 covers diagnosis, testing, and the first hour of labor.
Triton RV Repair quotes in writing before any repair begins. There is no charge for a recommendation that the repair is not cost-effective.
Frequently Asked Questions
How do I know if my fresh water tank is leaking versus a supply line?
A dropping water level in the fresh tank can mean a leaking tank or a leaking supply line, and telling them apart without a pressure test wastes time. Jesse's method is to isolate the tank by closing the outlet and the fill port, then pressurize the tank side alone with a hand pump to 5 PSI - far below operating pressure but enough to surface any active leak at a fitting or a crack. If the tank holds, the problem is downstream in the supply lines.
Can a polyethylene fresh tank be repaired or does it always need replacing?
Polyethylene welding is viable for cracks that run along the tank body and have not penetrated all the way through the attachment bosses. The repair involves grinding a V-groove along the crack, heating the tank wall and a PE filler rod simultaneously, and flowing the filler into the groove under pressure from a welding shoe. Done correctly, the weld matches the parent material strength within about 80 percent.
What causes RV fresh tanks to crack in Florida?
Polyethylene expands and contracts with temperature, and Florida's daily temperature swings - from a 68-degree night to a 95-degree afternoon - create repeated thermal cycling at every fitting boss. Over years, this work-hardens the plastic around threaded fittings and promotes stress cracking. Coaches parked in direct sun with the underbelly access panel removed accelerate this process by allowing UV to degrade the tank surface directly.
How do I sanitize a fresh water tank that has been sitting all summer?
A fresh tank left partially full through a Florida summer is a reliable incubator for biofilm and bacterial colonies. The warm, still water - often 85-90 degrees inside an enclosed underbelly - produces conditions that a 15-minute bleach treatment barely addresses. The correct protocol is a 100 parts per million chlorine solution held in the tank for four hours, followed by a complete flush and a re-fill test for taste and odor.
What is the correct way to fill a fresh tank that has been dry?
An empty polyethylene tank that has sat dry for months can develop a faint plasticky odor when first filled, particularly if it has been stored in heat. The first fill should be run to drain and repeated once before the water is used for anything other than flushing. This purges any off-gassing and confirms that no dust, insects, or sediment have entered through an open vent.
Sources and Further Reading
- Safari Water RV tank products - Polyethylene tank specifications and fitting compatibility for common RV manufacturers.
- EPA fresh water safety guidelines - Sanitization procedures and disinfection ratios for potable water tanks in recreational vehicles.