The purpose of a backflow preventer is to prevent the backflow we discussed above. Whether it's to protect a potable water supply line or to preserve sensitive equipment that only runs in a specific direction, having a backflow preventer installed is essential.

All things considered, installing a hot water recirculation pump in your home is a clear win-win. It substantially reduces waste, not only of water, but of your own time and money. So, what are you waiting for?

In terms of energy efficiency, an on-demand hot water recirculation pump is far and away the best option. Some recirculation systems have pumps that run constantly or on a timer, but both types inevitably waste energy. In contrast, a button-activated, on-demand model only functions as needed, which minimizes energy expenditures.

With the substantial amount of water they save, recirculation pumps represent a clear solution to the problem of wait times for hot water. If this solution were adopted on a wide scale, the total savings would be incalculably significant. That’s why, in an age when water is becoming increasingly scarce, every home should have a hot water recirculation pump.

Backflow may be caused by improper pipe sizing, so ensuring appropriate sizing is essential to help prevent backflow. The wrong pipe sizes may lead to an increase in water pressure, causing backflows in certain parts of the system.

One of the many advantages is that a backflow preventer is extremely versatile. Backflow preventers work in many different scenarios, from an irrigation system to a fire hydrant and even a fire sprinkler system.

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Considering the ever-increasing cost of water, it makes clear financial sense to invest in water-saving strategies, and to do so where they’ll have the biggest impact. Since a hot water recirculation pump can save an estimated 16,000 gallons per year in a four-person household, there’s no better place to start.

Wait = Waste By doing some simple math, we can get a clear picture of how much water is actually wasted by wait times for hot water. Let’s assume you have a generic low-flow showerhead that emits 2.5 gallons per minute (gpm) and it takes one full minute for hot water to arrive. That’s 2.5 gallons wasted per shower. Now, assuming you shower every day, let’s multiply that by 365—now you’re up to 912.5 gallons annually. Multiply that by 10 and that’s 9,125 gallons wasted over the course of a decade.

It’ll save money. As with most utilities, water rates have consistently risen over time, and particularly so in California, where residents pay some of the highest rates in the country. What’s more, rates are likely to rise further, and in some cases are already slated to. In San Francisco, for example, the Public Utilities Commission has approved incremental water and sewer service hikes over the next four years to finance improvements to the city’s water infrastructure. And it’s not just the big cities where water rates have and will continue to soar—even small communities are feeling the pinch of high prices.

If you've enjoyed this tidbit about backflow preventers, you may also like other articles such as T-Port Vs. L-Port or Why Choose Apollo Ball Valves. If you have additional questions about backflow prevention, or you'd like help with your particular system, feel free to contact us; we'd love to help you.

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Atmospheric Vacuum Breakers (AVB) are a type of backflow preventer that works well for low-hazard applications. These backflow prevention devices operate on a fairly simple concept, combining the mechanical abilities of a simple spring and a float. Typically, the pressure of the fluid opens the valve in the appropriate direction. However, when the system loses pressure due to backflow, the float falls, and the spring-loaded check valve closes.

A low-flow sink aerator won’t reduce waste while waiting for hot water to arrive. Photo: American Ratings Corporation ©2018

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Once this zone is filled, the second gate opens. This is normal water travel through a backflow preventer. When the inlet is shut off, both gates close and no backflow gets through.

It’s surprisingly affordable. Perhaps the best reason to get a hot water recirculation pump is the fact that it’s not very expensive, as far as home improvements go. Roman Scanagatta, owner of Roman’s Plumbing, Inc. in Petaluma, breaks down the typical cost: “To do a retrofit recirculating system in one bathroom, the pump and labor together runs $695. Each additional zone is $250, so if you wanted to do your kitchen and another bathroom, it would cost another $500 on top of that.” Of course, as one plumber’s rate, these prices aren’t definitive. However, given a ballpark estimate of $1,200, retrofitting all your home’s water fixtures will likely cost less than your annual water bill—which, going forward, will be substantially reduced.

It’ll save time. In this fast-paced day and age, we have less time to wait around for things, and that includes hot water. Plus, just as those small amounts of wasted water add up incrementally, so do the minutes spent waiting for hot water. Let’s say you spend two minutes each day waiting for hot water—over the course of a year, that amounts to 730 minutes, which means you’ll have squandered 12 hours standing by the tap. Like water, time is a limited resource, and a recirculation pump will allow you to utilize both more wisely.

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Backflow preventers are applied anywhere there is a cross connection in a potable water system, as these systems also direct wastewater, sprinkler systems, fire sprinklers, etc. They are the fail-safe standing between you and unsafe drinking water.

A Double Check Valve Assembly (DCVA) has double check valves that are, arguably, more complex than those listed above. They're a better choice than pressure vacuum breakers for certain high-risk applications (fire sprinkler systems, for example).

To fully understand what a backflow preventer is and answer questions like, "What does a backflow preventer do," we first need to discuss what backflow is.

Temperature fluctuations can also lead to backflow. This is because the water pressure may change drastically in response to temperature changes, especially in the case of frozen pipes. The change in water pressure can easily lead to backflow in a different part of the system.

But the shower isn’t the only place where hot water gets used. If you’re like most people, you prefer to wash your hands (as well as your dishes) in hot water—a wise practice, as it cleans more effectively than cold water. So, let’s assume you wait for hot water at a sink at least twice a day, your faucet has a 1.5 gpm flow rate and it takes a full minute for hot water to arrive. This comes to three gallons per day or 1,095 gallons annually. Add this to the total wasted annually for showering and you’re looking at roughly 2,000 gallons of water wasted per year.

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The solution: Hot water recirculation A hot water recirculation pump is a device that cuts wait times for hot water down from minutes to a few seconds. It does this through a complex process of recirculation, which consists of two simultaneous actions:

Pumps can be integrated as part of a new construction design or installed as a retrofit application. In the latter instance, the pump is spliced into the hot and cold water lines of the existing plumbing system.

If you want to prevent backflow, it can be helpful to understand what causes it. In our experience, there are several different reasons why you may encounter backflow, including the following:

By performing this dual process, a hot water recirculation pump can deliver near-instant hot water and conserve thousands of gallons of water per year, per fixture.

If backflow pressure is greater than upflow pressure, the second gate closes; if the second gate cannot close due to debris, the first gate will close, and the relief valve will open. Back siphonage is handled in the same way. Even if both gates are stuck open with debris, neither backflow nor back siphonage can contaminate the potable water, as the problem will be directed out from the backflow preventer via the relief valve.

The Pressure Vacuum Breaker (PVB) is more robust than the AVB system, but these backflow preventers work best for low to medium-risk applications, like your irrigation system or sprinkler system. It combines the mechanical properties of a spring, check valves, and a critical vacuum to help ensure that the system is protected against backflow.

By eliminating wait times for hot water, a recirculation pump conserves thousands of gallons of water per year. Photo: Mason Plumbing, Inc. ©2018

When you need to prevent backflow in your system, or backflow prevention is a legal requirement for your industry, you're in the right place. In fact, you can find backflow preventers--made by Apollo--right here on our website.

Since the mid-20th century, water conservation has gone from being a fringe concept to a standard practice, which is why water-efficient plumbing fixtures and appliances are simply the norm nowadays. However, despite these developments, there’s one case of water waste that remains widely ignored: wait times for hot water. Whether at the sink or the shower, the lapse between when hot water is turned on and when it arrives represents one of the leading causes of water waste today…and it’s time we started addressing it.

When a simple check valve is inadequate for the job, you need a backflow preventer. But knowing you need one and understanding how they work are two different things entirely. Unlike an inline check valve, which prevents fluid from traveling backward through the system, a backflow preventer is far more complicated, particularly because it does more than simply regulate backflow.

Causes of wait times What exactly causes wait times for hot water? And why do they vary from home to home? This boils down to two main factors:

WattsBackflow preventer

Backflow is when fluids within a plumbing system run in the opposite direction of where you want them to go. Let's say you're running an irrigation system, for instance. While connected water lines may run potable water supply and treated irrigation water side-by-side, a backflow of irrigation water into the potable water system would be disastrous, as it might lead to contamination of drinking water, resulting in disease and other health or environmental problems. Installing a backlow preventer is ideal in these cases.

Your backflow prevention device requires general maintenance to ensure that it functions as well as it should. While most of the backflow preventers on the market have safeguards in place to prevent complete failure, there are still opportunities for failure when you don't practise regular maintenance.

There are two gates (i.e. check valves), an empty space between them, and a diaphragm that is activated by pressure. As upflow water pushes against the first gate, exceeding a preset psi, it is directed to the reservoir of the diaphragm. When cracking pressure is reached, the diaphragm depresses and closes a relief valve. As pressure builds, exceeding the next preset psi, the gate opens, allowing the chamber to fill.

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To prevent backflow, as well as back siphonage, a backflow preventer incorporates a series of check points that respond to pressure. These points are check valves that open and close, allowing upflow travel and stopping reverse travel.

Of course, the figures we’re using here are merely for the sake of example—in reality, wait times for hot water vary considerably from home to home. However, while generalized, these figures are by no means unusual, and in some cases they may be modest in comparison to actual levels of waste. One thing is for sure: These levels of waste are substantial and need to be addressed.

So, what can you do? After all, you probably aren’t going to wash your dishes in cold water or start taking cold showers every day. You could use containers to catch the water, which is useful if you’re a gardener. However, if you don’t have any plants to irrigate, this may not be worthwhile (and it’s pretty inconvenient either way). Wouldn’t it be nice if there was a simpler solution?

Still not convinced? Even if you’re in favor of water conservation, it may not be a motivating factor for you, especially when it comes to making a financial investment. If that’s the case, consider these additional, practical reasons to invest in a hot water recirculation pump:

If you've been considering which plumbing device helps prevent a backflow, you already know that there are several types of backflow preventers on the market. Let's take a closer look:

We have found that installing a backflow prevention device is crucial to maintaining water quality. In some cases, the failure to install backflow preventers can lead to the contamination of an entire water source, rendering it unusable.

These are the main types of backflow preventers available for purchase. If you’re going to buy one, we’d recommend the double check valve assembly or reduced pressure zone assembly for most applications.

Because of the double check valve design, combined with the diaphragm and relief valve, a backflow preventer is practically foolproof. Fouls like debris, which may force a gate to be stuck open, are managed by a pressure equalization that will open the relief valve, alerting you there is a problem. Likewise, backflow is prevented in the same way--the valves respond to pressure.

A backflow preventer is typically installed anywhere in a piping system that involves major cross-connections. For example, a water authority might require backflow preventers for fire protection systems. The backflow preventer’s job in this case, is to prevent non-potable fire fighting water from contaminating municipal potable water.

Finally, you may encounter a similar situation to the one discussed above, but from different causes. When there's an increase in water pressure on the receiving side of the water main, you'll also encounter backflow as the water pipes try to equalize the pressure vacuum formed by the sudden pressure changes. This is known as reverse pressure.

We have found many benefits to installing a backflow prevention device. Some of these are fairly simple, while others make a significant difference. Let's discuss why you should consider purchasing one.

If you want to comply with regulations, it can be essential to install backflow preventers where two or more pipes meet. Simple check valves generally aren't enough to qualify as a complete backflow prevention system, even though they may be sufficient to prevent backflow in certain cases.

These causal factors are often exacerbated in homes built within the last 25 years. Why? Because newer homes tend to be larger, which creates increased distances between the hot water heater and water-dispensing fixtures. Furthermore, the plumbing systems in many modern homes were built with wide-diameter water pipes, as required by updated building codes. The result: Longer wait times and more wasted water.

There are two different types of situations to consider here. Back siphonage happens when there is negative pressure in the supply feed: a vacuum is created that allows water to siphon in the reverse direction. Backflow, on the other hand, is caused by back pressure--this happens when the pressure of the non-potable water is greater than the pressure of the drinking water as it is supplied from a distribution or source. Fluid flows from high to low pressure regions, resulting in contamination of the drinking water.

In our opinion, having a backflow preventer installed can also help safeguard your health. It does this by preventing contaminated water from entering potable water sources and preventing bacteria from entering places they don't belong.

A Reduced Pressure Zone Assembly (RPZA) is more advanced than some of the other listed options. These kinds of assemblies with reduced pressure zones are some of the most comprehensive backflow prevention systems on the market. In applications where it's vital to prevent contaminated water from entering your main water supply line, the RPZA system is ideal. It consists of several different parts, including:

When you take a closer look at the backflow preventer and how it works, you'll find that most backflow prevention assemblies rely on the use of check valves. Here’s how a backflow preventer works:

Another likely cause of backflow lies in sudden dips in water pressure. When there is a sudden dip in pressure on the main water supply line, the water pipes may begin pushing water backward to equalize the pressure in the system. This is also a type of backflow.