Flush-Safe is a water meter specifically designed for RV tank flushing and filling. It automatically and precisely delivers a preset number of gallons, then shuts off—preventing overflows and eliminating the need for manual monitoring. Unlike timers, Flush-Safe measures gallons of water, not time, for far greater accuracy and peace of mind.

Flush-Safe was developed by an experienced RVer traveling the lower 48 states and Canada over the last four years and camping at hundreds of sites. After personally overfilling the black tank on at least two occasions—once due to distraction and once due to a failed tank sensor—it became clear there had to be a better solution.

Many RVers admit that black tank overflows are almost a “rite of passage.” Tank sensors are notoriously unreliable, Many have turned to garden timers or digital meters as workarounds— but most find them inaccurate, unreliable, and ultimately more trouble than they’re worth. That’s exactly why we developed Flush-Safe: a purpose-built, water meter designed for RV use—accurate, automatic, and engineered to take the guesswork out of tank flushing.

Curious how Flush-Safe came to be? Read Our Story to see how one RVer’s experience turned into a smarter tank-flushing solution.

A digital water meter can show you how many gallons have passed through it—but it doesn’t shut off automatically. You still have to stand by and monitor the flow, manually turning off the water at the right time. That means you're just trading one chore for another.

Flush-Safe, on the other hand, is a preset water meter that automatically shuts off once the selected amount of water has been delivered. No guesswork, no hovering by the hose, and no risk of overfilling if you get distracted.

Sprinkler and garden timers measure time, not gallons. They’re designed to shut off after a set duration, but they can’t accurately control how much water is delivered—especially with fluctuating water pressure. Even models that claim to measure gallons are still time-based and just as inconsistent.

You could try timing the fill at each new campground and adjusting your timer accordingly—but most RVers have better things to do than run water tests at every stop. If you’re busy breaking camp or getting back on the road, babysitting a timer isn’t going to cut it.

Flush-Safe eliminates the guesswork by measuring the actual gallons dispensed and shutting off automatically—so you can get back to your travels without the mess.

Definitely! Since Flush-Safe measures gallons—not time—you can use it to flush gray tanks just as easily.

Most RVs don’t have an external fill connection for the gray tank like they do for the black tank—but you can still use Flush-Safe to flush your gray tank internally.

Simply empty the gray tank and close the valve. Then connect a hose to Flush-Safe, set it to your desired output. Place the hose in a sink or shower drain. Turn on the water and let Flush-Safe do the rest.

Caution: Make sure the hose is secure and won’t jump out of the sink or drain during filling.

Absolutely! Flush-Safe is safe for potable water use. All materials are non-toxic and noncorrosive.

If you are concerned about cross-contamination, consider buying a second unit dedicated to freshwater use.

Flush-Safe uses standard garden hose fittings, making it compatible with typical RV water systems. Simply connect one hose from your water source to the inlet side of Flush-Safe, and another hose from the outlet side to your tank’s flush or fill port.

For added convenience, we recommend using a short hose and a manual shutoff connector near your water panel to make setup and control even easier.

Flush-Safe is designed to be maintenance-free under normal use. However, if you’d like to sanitize it periodically — especially if using for freshwater filling — we recommend one of the following safe cleaning methods:

• Diluted bleach solution: 1 teaspoon of household bleach per gallon of water. Let sit for 15–30 minutes, then rinse thoroughly.

• White vinegar: Use a 1:1 mixture with water. Let sit briefly, then rinse completely.

• Pure sodium percarbonate: Mix 1–2 tablespoons in a gallon of warm water. Let sit for up to 30 minutes, then flush several times with potable water.

• RV-safe cleaning products: Use cleaners labeled for potable water systems. Always follow label instructions.

Be sure to rinse thoroughly and allow Flush-Safe to dry completely before storage. Only use mild cleaners that are safe for water system components. Avoid harsh household chemicals not intended for RV or potable water use.

Flush-Safe is engineered for long-term reliability and consistent performance. The internal mechanisms, including the precision gear system and valve assembly, are designed to deliver accurate water metering and dependable operation over many years of typical RV use. All critical components are constructed with high-quality, corrosion-resistant materials, and the housing is sealed against leaks with UV-stable, non-toxic plastics. Flush-Safe has been tested under real-world conditions, including extended high-pressure exposure and repeated cycling, to ensure it withstands normal use over multiple seasons. Replacement parts such as knobs and hose gaskets are also available through our website to help keep your Flush-Safe operating smoothly for years to come.

Back pressure refers to resistance to water flow after it passes through Flush-Safe — caused by downstream fittings, valves, or piping. Flush-Safe operates using the pressure difference between the inlet and outlet to accurately count gallons. If there is significant back pressure, the force of the incoming water jet that drives the internal gear mechanism can be reduced, which may slightly affect the volume registered at shut-off.

While the metering remains consistent under steady conditions, different pressure environments — including back-pressure or well-water systems with fluctuating inlet pressure — may cause some variation compared to a constant-pressure supply. For best results, Flush-Safe should be used in systems with uniform downstream restrictions and relatively stable water pressure.