Adding Septic tank Capacity.

[JoeJee]

We are in the process of adding a second living area and adding plumbing to shop. No final design yet but likely to have 1200-1500 sqft for new living area with 2-3 bath and a bath/shower/kitchen for shop. The existing home has 2100sqft, 2.5 bath, and 3 bedrooms. Existing septic is estimated 1000 gal. Leach field is stepped down and has three or four rows; looks like only the first row is enough b/c the other sections are clean.

Our plumber has suggest a few options and wanted to get some opinions about the suggestions and if other options are available.

1st) remove existing tank and install 1500-2000 gal tank depending on final design.

2nd) have second living area and shop on own 1000gal septic that ties into existing leach field.

3rd) put another 1000 gal septic in series to create a 2000 gal septic system

 

[John Gayewski]

How many bedrooms are you adding?

 

[Sponsor]

 

[Storm rider]

In my neck of the woods the health department will tell you what they are going to require based upon your building plans, before they authorize the building department to issue your building permit.

 

[Jeff H Young]

dont know if adding a bigger tank helps if it dosent leech out enough for the additional load. My guess is you would need copy of soils report and info on what is existing to figure out if leech field is sufficent. or run a complete new system for your addition? call the existing system good on its own

 

[John Gayewski]

My question was how many bedrooms are you adding? The reason I asked this question is because generally you don't need to add capacity to a septic system unless your adding bedrooms. I.e. more people equals more water use equals more septic capacity. You could have a million square feet, and 200 bathrooms. If there are three people using the space max, then you only need three people worth of septic.

This also helps decide how you add if necessary.

 

[Gsmith22]

How many bedrooms are you adding?

This. The design of any septic system is based on how many bedrooms you have. If you aren't adding bedrooms, you aren't adding occupants. And occupants are what use water. That being said, if your addition requires a larger septic SYSTEM for some reason, the SYSTEM needs to be increased. The tank(s) and field work together. You can't just make one of them larger if flow is increasing into the SYSTEM. its a SYSTEM.

 

[JoeJee]

Thank you everyone for the replies. I am working with a septic company for this and the suggestions on OP is what they said they could do per country requirements.

Leach Field: contractor said it is fully capable of handling several homes. Risers are planned for each leach line for inspections to monitor just in case.

We expect to add up to 3 bedrooms and 3 baths for a total of 6 beds, 5.5-6.5 baths. The new shop bathroom/shower/kitchen usage is an unknown. Original it won’t have much use (3 people periodically) but it could have more people in there after a few years.