Petroleum Storage: HydroGuard® Monitoring System

HydroGuard® Monitoring System guards against leaks and liabilities

Envirotank recommends the HydroGuard® Monitoring System for double-wall tanks because of its superior leak detection capability. By filling the cavity between the inner and outer tank walls with a non-hazardous liquid, hydrostatic pressure is continuously applied to both the primary and secondary tank. This system is capable of detecting tank leaks in either the primary or secondary tank walls for all installed conditions.

The HydroGuard® Monitoring System, with a stand pipe, can also serve the dual function of a precision tank test.

The system has been independently tested and statistically validated to meet EPA and AIP criteria as a precision tank test. Using a stand pipe, the system has been shown to be capable of detecting leaks as small as 0.76 litres per hour with a 99.9% probability of detection and less than a 1.2% probability of a false alarm.

Envirotank Double-Wall tanks include the fibreglass reservoir necessary for the HydroGuard® Monitoring System. The HydroGuard® Monitoring System provides continuous leak detection while avoiding false alarms caused by changes in product temperature, product level or groundwater conditions.

How HydroGuard® Monitoring System works

Normal Conditions

The reservoir liquid level will be stable if both the inner and outer tanks are tight. The optional reservoir sensor will activate an alarm if the reservoir drains or overfills.

Inner Wall Breach

HydroGuard® fluid drains into the primary tank causing the reservoir liquid level to drop. No petroleum product escapes from the primary tank to contaminate the annular space.

Outer Wall Breach

Groundwater Below Tank Top
If the groundwater is below the tank top, the HydroGuard® fluid drains into the ground, causing the reservoir liquid level to drop.

Groundwater Over Tank Top
If the groundwater is over the tank top, the reservoir will fill up with groundwater.


Wet Annular Space

HydroGuard® Hydrostatic Monitoring System

  • Use antifreeze solution in cold climates.
  • Maximum burial depth from tank top is 2.1m below grade.
  • Monitoring cavity must be vented to the atmosphere at all times.
  • After installation, set the liquid level in the reservoir so reservoir is half full.
  • The optional reservoir sensor if installed will alarm for preset events.

Monitoring System with Liquid Sensor

Typical configuration for an electronic sensor or manual dipstick.

  • Use the standard monitoring fitting.
  • Monitoring cavity can be vented or sealed.

Dry Annular Space

Envirotank also provides the option of a factory-installed “drawstring” at the annular space monitoring fitting, to assist in positioning liquid sensors at the bottom of the annular space.

If your tank is ordered with a dry annular space, but fitted with the optional fibreglass reservoir (instead of a monitoring fitting), the drawstring will be positioned within the reservoir.


PDF Brochure >>     Next: Specifications >>

View list of

Approved Envirotank
Installers (AEI)

Click here >>

Latest News & Info

Conder Environmental Solutions

Envirotank would like to announce that Conder Environmental Solutions and Envirotank have signed a technology supply agreement to manufacture and represent their products under license in the Oceania region. The agreement allows Envirotank to manufacture and provide quality Conder storm water treatment devices and “Clereflo™” separator products meeting ENBS-858 to all industries in the region.

ACAPMA Convenience and Fuel Industry Conference

Envirotank to exhibit at the ACAPMA Convenience and Fuel Industry Conference September 11th to September 14th.