An “alternating valve” or a “switching valve” refers to a device that allows you switch from one absorption field to the other in a gravity type septic system. The brand name of a popular valve is the Bull Run valve.
What are the benefits of two field?
Using one field at a time allows the other one to rest and dry out. This switching back and forth will help to prohibit a bio-mat growth in your absorption field and should make your system last exponentially longer (than if you had just one field).
I recommend switching your valve every year on a specific date like the fourth of July or first day of spring. If these dates don’t suit you, don’t be afraid of creating your own special date like “Were having a party to switch our septic day!”
Here is another way to manage your valve. Put on Valve on position 1 during odd years and position 2 during even years. I think the party idea is better.
Why would I have two absorption fields?
- When your system was installed, you might have had the wisdom and foresight to have two fields installed
- When you have a repair system installed, you may have enough room in your yard to keep the new and existing field separate. This is a great thing (like finding a box of perfectly good donuts on the side of the road)
- If you are putting a valve on a new and failed system. Switch the valve to the new system for three years. Then switch the alternating valve yearly to alternate between the two. Three years of rest will allow your failed system to regain as much of it’s absorption capacity as possible.