Wednesday, April 30, 2014

How Does The Spindown Filter Work For Well Water?


I was told by my contractor I need a ‘spindown filter’ for our house. We get our water from our own well and we get fine flaky sediment coming from our well. Where are the filters installed, before or after our pressure tank? How often do I need to change or clean the filter?

- Larry S


Spindown filters have filter screens that come in different mesh sizes, such as 30 mesh, 60 mesh, 120 mesh. The mesh size refers to the number of holes in the screen per square inch.
The spindown filters are cleaned by opening the bottom valve for several seconds and letting the water pressure flush and rinse the screen of the spindown filter.
rusco spin down filters
Rusco Spindown Filters

The filter screen might need to be flushed every day, once a month, or longer depending on the amount of the sediment and how much water is being used. An auto-flush-valve is recommended if you want it to be done automatically. The auto-flush valve “AFV” or also called auto-purge valve opens up automatically for 3 seconds, as many times as once a hour or once every 24 hours, and this keeps the screen clean.

rusco auto flush valve
Rusco Auto-Flush Valve
Generally we recommend a 30 to 60 mesh size, as the spin down filters work best for larger particles. If you get too fine a mesh size, say 250 or 500 mesh, the particles may not flush out well, and in that case, you may need to remove the filter screen and brush it off to clean it. This is easy to do, but if there is also a lot of fine sediment, it is better to use a higher capacity filter housing and filter cartridge rated for 1 to 50 microns after the filter strainer spindown.

Filter cartridges such as a ‘big blue’ whole house filter, can hold many times the amount of sediment that a spin-down filter can hold. We have many customers who use a combination of a spin-down filter first, followed by a big blue whole house filter housing, and then in some cases, a Sediment Backwash Filter as a final stage.
big blue whole house filter
Big Blue Whole House Filter
One point is, the spin down filter should be installed AFTER the pressure tank so there is water pressure available to flush it. Generally, we do not recommend it being installed before the pressure tank, as this can cause too much back pressure on the well pump and cause pump damage if the filter screen becomes clogged. If it must be installed before the pressure tank, be sure to use a pressure relief valve on the pipe, to prevent well pump damage.

plumbing diagram
Thanks for writing to us and we hope this can help solve your problem. If you have any further questions, or would like to update us on your progress - we love pictures and testimonials! - you can reach us at or on Facebook. Thanks for the letter!