Backflow preventer installation costs are always a hot topic. I meet with water authority officials from across the country on a regular basis. Regardless of which region of the United States I happen to be in, the questions concerning backflow preventer installations are remarkably the same. One question I would like to address is asked virtually everywhere I go: Does it cost more to install backflow preventers above ground?
Utility Vaults Are Unsafe
Our general message at Safe-T-Cover is to get all backflow preventers out of below-ground vaults and outside of buildings. The safety benefits alone fully justify the best practice of installing backflow preventers above ground and in an ASSE 1060-certified enclosure. But another perk to enclosure installations is the enormous savings in cost.
Backflow Enclosures Save Money
We estimate that an RPZ backflow preventer installed above ground in an ASSE 1060 enclosure will save you anywhere from 10%-15% in total installation costs over a DCDA installed in a below-ground vault. Obviously, there are huge cost variables across the country with labor costs, equipment, property, contractors, etc. But if you average those variables out, and drill down apples to apples, the RPZ above-ground in an enclosure model will conservatively save you 10%-15% anywhere in the U.S.
Additional Backflow Preventer Installation Costs Tied to Vaults
In addition to the installation cost savings, there are also cost savings in routine maintenance. Since a below-ground vault is considered a confined space by OSHA, just entering a vault incurs huge costs on a regular basis.
To enter a confined space, at a minimum you must account for gas detection, fall protection, ventilation, and communication. All of these safety precautions have huge routine costs that should be considered when deciding where to install your backflow preventer. Furthermore, some backflow testers charge higher costs for testing inside vaults because of the increased safety precautions required to enter confined spaces. In a nutshell, maintenance and repairs cost more when your backflow preventer is in an underground utility vault.
Above-ground aluminum enclosures are also very good at protecting backflow prevention assemblies. When they’re ASSE 1060-certified, they offer protection from the elements, freeze protections (with a slab-mounted heater), and can hold thousands of pounds (just in case it snows—a lot).
An above-ground backflow enclosure won’t flood, like a utility vault. A cross-connection control investigator in a large midwestern city told us something very scary. He says he’s opened thousands of vaults during his 30-year career and only one out of 100 is dry. And when the vault floods, the backflow prevention device is often submerged in water.
This not only adds expense but also another danger. Experts at the University of Southern California write about the dangers of flooded utility vaults in their publication, Cross Talk. They recommend that all backflow prevention assemblies be installed above-grade.
When comparing the costs of installing your backflow preventer above ground or below ground, there really is no comparison. The above-ground model will save you money on initial installation, routine maintenance, and long-term life of your project.
Stay Up To Date
When engineers design water systems, it’s important that they keep up with the latest regulations regarding backflow preventers. Their contributions help provide long-term safe drinking water for client communities.
Water districts must stay up to date on regulations and enforce them. That includes annual testing of backflow preventers and working closely with plumbers and engineers. This combined effort between water districts and staff, as well as the local government, will ensure everyone is doing what they can to keep our drinking water safe.
If you’d like more information before designing your next backflow preventer installation, check out our design guide. It contains a wide range of enclosure options and considerations that are available.