# Aerator pump size for septic tank



## spaceman spif (Jul 28, 2009)

The septic aerator pump kicked the bucket after 20 faithful years of service at my Mom's house. I'm looking to save her hundreds by buying and installing a replacement on my own, but I have some questions about the size.

The old pump was a 1/2 Hp, 10 cfm pump. Do you base the cfm on the size of the septic tank or on the amount of water usage in the house? At the time the house was built, 4 people lived there. My Mom lives alone now, so there's minimal water usage each month. Don't know the size of the tank, I'm still trying to find that out.

If I can step down to an 8 cfm pump without any problems, that would save me a couple hundred dollars. Well, actually it would save my Mom a couple hundred dollars. :wink:


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## LateralConcepts (Jun 6, 2010)

spaceman spif said:


> The septic aerator pump kicked the bucket after 20 faithful years of service at my Mom's house. I'm looking to save her hundreds by buying and installing a replacement on my own, but I have some questions about the size.
> 
> The old pump was a 1/2 Hp, 10 cfm pump. Do you base the cfm on the size of the septic tank or on the amount of water usage in the house? At the time the house was built, 4 people lived there. My Mom lives alone now, so there's minimal water usage each month. Don't know the size of the tank, I'm still trying to find that out.
> 
> If I can step down to an 8 cfm pump without any problems, that would save me a couple hundred dollars. Well, actually it would save my Mom a couple hundred dollars. :wink:


You could probably save your mother hundreds of dollars on her electric bill by eliminating it all together. Just my 2 cents


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## spaceman spif (Jul 28, 2009)

LateralConcepts said:


> You could probably save your mother hundreds of dollars on her electric bill by eliminating it all together. Just my 2 cents



When I read the first part of your reply, a gecko with an Australian accent popped into my head....:yes:


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## spaceman spif (Jul 28, 2009)

Whoops...accidentally submitted my reply before finishing.

Can the tank work without an aerator? Doesn't the bacteria in the tank need the oxygen?


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## LateralConcepts (Jun 6, 2010)

spaceman spif said:


> Whoops...accidentally submitted my reply before finishing.
> 
> Can the tank work without an aerator? Doesn't the bacteria in the tank need the oxygen?


No problem mate :wink:

Tell me more about the septic system. Do you know what size the tank is? When it was installed? What type of leaching system/drain field do you have? If you're unsure, your local health department may have records. Post a picture if you can. Most aeration systems are just gimmicks.


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## spaceman spif (Jul 28, 2009)

All I know is the tank and pump and all were built 20 years ago. My Mom is currently digging through her records to see if she can find out any more.


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## LateralConcepts (Jun 6, 2010)

spaceman spif said:


> All I know is the tank and pump and all were built 20 years ago. My Mom is currently digging through her records to see if she can find out any more.


Do you have a local health department that regulates permits? 

They may have the records you need. If not, they would definitely have the answers you need. i.e. Whether an alternative (aerated) system is even necessary based on soil conditions, etc.


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## VIPlumber (Aug 2, 2010)

> You could probably save your mother hundreds of dollars on her electric bill by eliminating it all together.


My thoughts exactly! I was caught out by this question. I've lived on 3 septic systems in my life and none of them have had an aerator.

The only reason I can think of for an aerator to be there is if your mom's soil is anaerobic. Meaning that there's not enough air penetration through the soil to the septic field to help break down the sewage.


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## LateralConcepts (Jun 6, 2010)

So is your mom having problems with the septic system, back-ups, or is it just that the aerator stopped working?

Here's a good guide:
http://www.epa.gov/owm/septic/pubs/homeowner_guide_long.pdf


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## spaceman spif (Jul 28, 2009)

The aerator stopped working.

Got some more info - county codes require an aerator, and the tank is 1500 gallons.

So my next question is this...can I use a smaller CFM aerator, but set the timer to run a little longer so the total amount of air pumped in is the same, it just takes a little longer? Or would a smaller CFM pump have trouble pushing air through the diffuser and I'm asking for trouble?

I'm also trying to find out who originally did the installation and get some info from them. If they're still around!


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