Onsite on Small Lots

Before agreeing to take a project with small lots, what are some of the first questions to ask the developers about the properties?  

As lot sizes for homes continue to shrink, engineers and designers have had to get creative with their septic system designs – like squeezing a tank beneath a backyard deck or stashing it in the homeowner’s basement. However, with some good qualifying questions and innovative solutions, wastewater treatment on small lots is not only possible but beneficial for all interested parties.  

Bill Hensley, senior systems engineer at Orenco Systems, spoke with Angela and Shawn, podcast hosts of “Make It Clear,” about considerations when designing treatment systems on small building lots. He recommends these seven questions.  

1. Is the project new construction or a replacement system? New construction gives designers a blank slate to create a wastewater treatment system from scratch, while a replacement requires a different kind of planning. “If it’s a replacement system, we may have existing infrastructure and buildings to figure out how to work around,” Hensley said. 
2. Is it possible that a municipal sewer line will come through the neighborhood? If so, when? Will the homeowner be required to connect to it? “Being able to plan accordingly could potentially save the homeowner a lot of money,” Hensley said.  
3. What is the home’s square footage? How many bedroomsdoes it have? The number of people living in the home will help determine the system’s size. “We can start getting an idea of how large of a treatment system that we potentially need,” Hensley said. 
4. Are site plans available that show the site’s existing infrastructure and drainfield? “Do they show anything we might need to avoid, like water lines, heritage trees, or plants?” Hensley said. “And having an understanding of how old some of that equipment like their septic tank is, is all good to know.”  
5. Has the site been evaluated to determine the type of soil classification and perk rates? Is the soil coarse and sandy, loamy, silty, or clay that’s hard as concrete? “For new sites, how has the site been evaluated to determine the type of soil classification and the perk rates?” Hensley asks. “Because that’s going to come into play for the designer.”  
6. What does thelot’s topography look like? How steep is area for the treatment system? Having sufficient square footage is first and foremost, Hensley said, but what that square footage looks like depends, too. “You might have a lot that looks like it’s sufficiently sized, but if it’s really steep, it might limit what you can actually do,” he said. “So sometimes, when you start getting in terrain, that’s where maybe drip irrigation starts looking good.” 
7. Does everyone have a thorough idea of the costs associated with an onsite system? Not just the capital costs, but the long-term operating costs and life expectancy of the system, too, Hensley said.“It really helps the homeowners or developers make wise decisions on the direction they need to go,” he added.  

Learn more pro tips by listening to the Make It Clear podcast, “Treatment on Small Lots,” which can be found at Orenco.com/resources/podcasts or through your favorite podcast platform.