Under what condition are dual pumps required in a system?

Dual pumps are required in a system when the daily flow exceeds 1,000 gallons per day. This requirement is put in place to ensure adequate reliability and performance of the on-site sewage facility. High flow rates can lead to significant strain on a single pump, increasing the likelihood of pump failure or inefficiency in handling the wastewater.

Having dual pumps allows for one pump to operate while the other serves as a backup, providing continuous service even if one pump encounters an issue. This redundancy is especially crucial in high-flow situations, where any interruption can lead to system failure and potential environmental contamination.

In contrast, the other conditions mentioned do not necessarily warrant the use of dual pumps. Lower flow rates, such as those under 1,000 gallons per day, generally do not require the additional backup provided by a second pump. Similarly, multiple tanks and gravity-fed systems can function adequately with a single pump, depending on their design and flow expectations. Thus, the specification for dual pumps is primarily driven by the need to manage higher daily flows effectively.