**John:
From Rhode Island:
.5.2 Calculating the flow trial volume
**Normal wastewater flows vary over the course of a day, peaking during the
morning and evening hours when people are most likely to use the kitchen, bathroom and laundry facilities. The greatest flow that may enter a system during an hour of time is called the peak one-hour flow. As it is typically the most stressful condition experienced by a system, the peak one-hour flow is also the condition that the flow trial is designed to approximate (i.e., peak one-hour flow = flow trial volume).
An examination of the literature indicates that peak one-hour flow can be
estimated as 12 times the average hourly flow or half the daily flow. Systems in RhodeIsland are designed based on the daily flow (i.e., design flow = daily flow), which can be calculated as 150 gallons per bedroom per day.10 Therefore, flow trial volumes can be calculated as half the design flow or as the number of bedrooms times 75 gallons.
Table 5.4 indicates flow trial volumes for homes relative to number of bedrooms and design-flow volumes.
**Table 5.4 Minimum Flow Trial Volumes Relative to Number of Bedrooms and Design Flow
Number of Bedrooms/ Design Flow (Gallons/Day)/ Flow Trial Volume (Gallons)
**2 300 150
3 450 225
4 600 300
5 750 375
6 900 450
My comments:
As you can see, I’m the ultimate sceptic. On house issues/repair costs that I have verified/seen the need for, I feel confident with estimates from good contractors. Using a full day volume for a flood test is still something I’m not confident with, even when from septic tank installers. Maybe less confident from installers as they have the most to gain!!! This culture is increasingly “All about the dollar” so I trust less and less. The full load test may generate a job that does not have to be done- good for the installer and makes the inspector look real good to the purchaser.