Which Septic Tank?

[s219]

Yeah, I am smelling some BS on that septic guy's story as well.

Our state also sizes by number of bedrooms, assuming two persons per bedroom. There is no "bare minimum" -- there is what is allowed by the health department, and that's it. You can upsize the number of bedrooms to allow for future expansion. In our case, we have a 3 BDR house being built, but sized the system for 4 BDR to allow for future expansion (ie, addition). This has nothing to do with extra capacity for normal use, but rather, to allow us to continue using the existing system if we ever add a 4th bedroom on to the house. Systems are already designed with plenty of over-capacity given a rated number of bedrooms.

We need to have an area designated for the primary drainfield, as well as an area designated for future use, called the reserve. Normally, expected life out of a drainfield is 40-50 years at a minimum. If a drainfield fails or reaches end of life, you'd install the new field in the reserve area.

Soil conditions play a big part in the size of the system, as well as how it's designed and if it needs "alternative" technology, which can pace or "dose" the amount of effluent going into a drain field. All of this is factored in, with number of bedrooms, when designing the system and requesting a permit from the health department.

As I mentioned earlier, a larger tank will not increase the effective capacity of the system to handle additional load like parties, company, etc. That seems to be a real common misunderstanding. The only time that comes into play is in an alternative system that has a reservoir tank that works in conjunction with metered dosing into the drain field. For a conventional system, the capacity is completely dependent on how much effluent the drainfield can handle. Tank size does not affect that -- once the tank fills up, the flow rate out to the drainfield is the same as the flow rate in from the household. Every flush into the tank is going to push an equivalent amount of liquid out into the drainfield, no matter how big or small the tank is.

 

[Pettrix]

As I mentioned earlier, a larger tank will not increase the effective capacity of the system to handle additional load like parties, company, etc. That seems to be a real common misunderstanding. The only time that comes into play is in an alternative system that has a reservoir tank that works in conjunction with metered dosing into the drain field. For a conventional system, the capacity is completely dependent on how much effluent the drainfield can handle. Tank size does not affect that -- once the tank fills up, the flow rate out to the drainfield is the same as the flow rate in from the household. Every flush into the tank is going to push an equivalent amount of liquid out into the drainfield, no matter how big or small the tank is.

Thank you all for the input, I appreciate it.

If what you say is true, then a 500 gallon septic tank would perform just as well as a 2,000 gallon septic tank. If a larger tank does not increase its ability to handle large loads (ie, parties, families) and if a gallon going in is a gallon going out to the drain field, why do they make larger tanks, for what purpose?

Well, I called and talked to the county engineer, here is what my health department stated in regards to getting a LARGER than required septic tank:

* Longer waste retention times due to the larger capacity
* Allows for better waste breakdown and waste separation
* Less carry-over of scum and sludge to the 2nd chamber
* Results in much cleaner effluent
* Larger septic tanks require less frequent cleaning/pumping
* During peak loads (parties, holidays) the larger tank is less likely to carry over solids to the effluent filter because of the larger capacity and breakdown area
* Allows for future expansion of the home & family size
* When the septic tank is upsized, the size of the leachfield will also be increased
** He said a 1,500 gallon septic tank can take-on 650 gallons of waste per day while a 2,500 gallon septic tank can take-on 1,300 gallons of waste per day ** That is double the daily capacity!!


The county engineer from the health department states there are feasible benefits for oversizing the tank and that a larger tank WILL increase the effective capacity of the system to handle additional load like parties, company.

He said that if the average sewage flow rate was 650 GPD - a 1,500 gallon tank would be recommended. He gave out these numbers and I scribbled them down as fast as I could:
300 GPD = 1,000 GAL tank
1,300 GPD = 2,500 GAL tank
3,200 GPD = 4,200 GAL tank

So size does matter and a larger tank will make a difference.

 

[Pettrix]

All of this makes sense except for the last statement as stated. The field size would be an additional specification. If you upgrade the tank, will they specify a larger field? I would if I could. I'd say no BS.

Yes, the larger tank would bring with it a larger leach field but we are talking pennies on the dollar here to run a few more lines. I can get the larger tank and larger field installed for $2k or less. This will give me double my capacity so when family visits or I have a party, I am not worried about having the system fail and backup into my home. That $2k is well worth the piece of mind it will bring. Not to mention the long term reliability of a better built system.

After the talk with the engineer, I am sold on the larger tank idea. He also mentioned that he has never heard of a system problem because it was oversized but he has had to deal with thousands of problems due to the system being overburden due to heavy loading and the undersized system size could not handle the extra sewage loads thrown at it.

 

[Pettrix]

The times with the most septic problems occur after Thanksgiving and Christmas. You got large family & friend gatherings, sometimes staying at the home for a week or more. So the 1,500 gallon system that was meant for 600 GPD is now getting 1,000+ GPD of use. In a matter of 2 days, the system is overburdened and failed, causing either solids to go into the leach field and/or backup sewer waste into the home.

Nothing like having Christmas dinner and then having raw sewage back into the home and permeate the air and floor with deadly and smelly waste. I've seen it happen to a friend of mine, he had to ask his relatives staying at this home to go and stay at a hotel. He then had to pay $1,000 dollars to have a septic pumping company come out at Christmas Day to pump the tank. That will be a Christmas to remember....

 

[reggiejr]

If you want to better your system don't waste your money on an enormous 2500 gallon tank a 1000 gallon is typical around here.
I would much rather invest in a larger field vs bigger tank size.
If your system is installed correctly and the tank is pumped out every 3-5 years you should be all set for a very long time.
I like the enviro septic system it can handle large volumes of water and uses up less space than a traditional field.
I installed this system at my brothers house a few years ago and was extremely impressed with this system.
I like the use of sand instead of rock it is much cheaper too.And you can clean the field if it ever got clogged up with solids.
It is a wicked versatile type system that can be installed in almost any type of terrain check it out you'll see lots of on site examples.
There is lots of great info on their website.Enviro-Septicｮ Septic System | Leach Field | Onsite Wastewater Treatment | Presby Environmental

 

[s219]

Thank you all for the input, I appreciate it.

If what you say is true, then a 500 gallon septic tank would perform just as well as a 2,000 gallon septic tank. If a larger tank does not increase its ability to handle large loads (ie, parties, families) and if a gallon going in is a gallon going out to the drain field, why do they make larger tanks, for what purpose?

Well, I called and talked to the county engineer, here is what my health department stated in regards to getting a LARGER than required septic tank:

* Longer waste retention times due to the larger capacity
* Allows for better waste breakdown and waste separation
* Less carry-over of scum and sludge to the 2nd chamber
* Results in much cleaner effluent
* Larger septic tanks require less frequent cleaning/pumping
* During peak loads (parties, holidays) the larger tank is less likely to carry over solids to the effluent filter because of the larger capacity and breakdown area
* Allows for future expansion of the home & family size
* When the septic tank is upsized, the size of the leachfield will also be increased
** He said a 1,500 gallon septic tank can take-on 650 gallons of waste per day while a 2,500 gallon septic tank can take-on 1,300 gallons of waste per day ** That is double the daily capacity!!


The county engineer from the health department states there are feasible benefits for oversizing the tank and that a larger tank WILL increase the effective capacity of the system to handle additional load like parties, company.

He said that if the average sewage flow rate was 650 GPD - a 1,500 gallon tank would be recommended. He gave out these numbers and I scribbled them down as fast as I could:
300 GPD = 1,000 GAL tank
1,300 GPD = 2,500 GAL tank
3,200 GPD = 4,200 GAL tank

So size does matter and a larger tank will make a difference.

I think you have a gross misunderstanding, and you need to be more clear about the difference between "tank" and "system". The numbers you are throwing around, and the implied increases in capacity with size, only apply if you design the whole system to match. Which means a bigger tank needs a bigger drainfield in order to actually increase capacity.

GPD, gallons per day, is a flow rate. Flow rates govern the amount of effluent discharged into the drain field. The tank acts as a reservoir in between, but will not increase/decrease the amount of gallons per day that a given drain field and soil condition can support. That is the bottom line. Flow rate is independent of tank size. A bigger tank won't magically allow the drain field and soil to handle higher GPD.

Larger systems meant to handle larger requirements will need both a bigger tank and a bigger drain field. These things scale together. In order for the septic tank to do its thing, it needs to be the right size. And to meet the design requirements, it needs to be discharging into a properly sized/designed drainfield. They go hand in hand.

 

[s219]

Yes, the larger tank would bring with it a larger leach field but we are talking pennies on the dollar here to run a few more lines. I can get the larger tank and larger field installed for $2k or less. This will give me double my capacity so when family visits or I have a party, I am not worried about having the system fail and backup into my home. That $2k is well worth the piece of mind it will bring. Not to mention the long term reliability of a better built system.

That is an entirely different ballgame than you have been explaining, and that makes sense. You're actually talking about a larger capacity system overall, not just a larger tank. I think that should have been more clear up front -- seemed like you were just looking at adding a larger tank for $700 more, which would not increase capacity by itself. If you are going with a larger system capacity, with tank and drain field sized to match, then that is good.

Around here, it cost about $1K for each additional bedroom (2 people) of capacity added to a system under optimal soil/installation conditions.

 

[boggen]

if you ever plan on a garbage disposel unit for the sink. getting a larger septic tank and leach field would be the thing.

as far as concrete or other type of septic tank. simply do a search for "septic tank" on google. you can normally have septic tanks shipped fairly easily. though some time spending on size, may require 2 halves of a plastic or like septic tank plastic welded or like together at your house.

there are multi types of leach fields, from the old 4" holed or slotted pipe, to new age upside down U shape tunnels for leach fields. plus multi other type of leach fields pending on your soil conditions. if you have the space, and even if it means taking out a good size tree or 2 now to get the leach field in a good spot. i would most likely do it. for long term doings. most of the problems just friends / family / neighbors. that have had problems with leach fields, have been high water table. or poor run off water drainage around the leach field. causing the leach field to get to much water into it. and cause problems. others have been simply not a large enough leach field.

as far as septic tank, a larger septic tank can help, more so when ya got bozo's toss garbage down the toilet, that is not bio degradable, condoms, tampons and wrappers for them, dumping or using chemicals for cleaning that can quickly wipe out a septic tank bacteria growth. ya got them city folks that live on city sewers, and then ya got them out of town folks. that have learned how to do things.

 

[Pettrix]

That is an entirely different ballgame than you have been explaining, and that makes sense. You're actually talking about a larger capacity system overall, not just a larger tank. I think that should have been more clear up front -- seemed like you were just looking at adding a larger tank for $700 more, which would not increase capacity by itself. If you are going with a larger system capacity, with tank and drain field sized to match, then that is good.

Around here, it cost about $1K for each additional bedroom (2 people) of capacity added to a system under optimal soil/installation conditions.

Sorry about not clarifying that. The larger septic tank design also included a larger drain field design with a D-Box and valve with the option to alternate drain lines if needed. That was what the septic installer was stating. He said to oversize it and I will be happier in the long run.

Not to be gross but I have a serious question:

I have a family member that had chemotherapy and might need it in the future. The chemotherapy would cause them to throw up a lot. How tough on the septic tank system is vomit?

 

[dmccarty]

Sorry about not clarifying that. The larger septic tank design also included a larger drain field design with a D-Box and valve with the option to alternate drain lines if needed. That was what the septic installer was stating. He said to oversize it and I will be happier in the long run.

Not to be gross but I have a serious question:

I have a family member that had chemotherapy and might need it in the future. The chemotherapy would cause them to throw up a lot. How tough on the septic tank system is vomit?

I have a family member that had to undergo Chemo twice. The load on the septic system was not an issue. Since this is a new house you will have a 1.6 GPF toilet so unless the person is sick hundreds of times a day it is not going to bother the septic system, and frankly at the level of use, you have bigger problems than the septic system.

While one should design the system for peak load, your numbers are assuming that you actually produce that much waste per day. Look at my numbers I posted earlier. Our system is already over designed by the state regulations. The over design is even larger when you compare are ACTUAL waste production. Do you think your system will NEED to handle 1,300 gallons a day? Worse case the four of us are producing 300 gallons a day. Your waste production is from flushing the toilet, showers/baths, washing clothes and dishes. We have low flow shower heads and toilets. Our shower head uses less than 1GPM as do our faucets. The dishwasher is supposed to take 10 gallons per load and I think our front loading clothes washer is the same. Given that it costs money to pump water from the well we conserve water. That save money on getting the water and getting rid of the used water. We conserve water because it is our well and we have a finite supply though our well is very productive.

40g - 4x10 minute showers a day at 1 GPM.
64g - 4 people flushing the toilet 10 times a day at 1.6 GPF.
10g - 1 dishwasher load.
100g - 10 loads of clothes at 10 gallons per load.
10g - Misc use, hand washing, brushing teeth, etc.
--------
224 gallons per day.

The 224 GPD is is high. I don't think we take 10 minute showers, I doubt we do 10 loads of washing a day so 224 is on the high side and we don't flush the toilets 10 times a day either.

Yet our septic system is sized for 1,000 GPD. By the way, I assume you are talking about having a conventional septic system. If you have a non conventional your system costs with the large system are going to increase. If you have poor soil like we do in our area, a larger leach field may not even be possible to handle a larger load. There are parcels in my area where one would be lucky to get a perc for a three bedroom house. Adding capacity would not even be an option.

I don't know the capacity of the pump truck that pumps our tank but at some point there could/should be an increase in the pump charge for a large tank. The guy does have to spend more time pumping and dumping the load. He might have to make more than one trip to finish pumping out the tank.

I really think the NC state regulations assume TOO much water usage in this day and age of Federal water conservation regulations.

Figure out how much water you think you will use per day, then figure in your peak loads for holiday visits, then focus on the septic system size.

Later,
Dan

 

[MotorSeven]

Pet, if you have the extra jingle in your pocket, go for it.
Here a 3br 2 ba system installed is under $3k and that is what I am putting in but I probably will add a few more sticks(20'ea) of drain line. Some up-sizing does make sense. For instance, when I had my shop/living quarter system put in 5 years ago my installer told me the difference in price from a 750 gallon to a 1,000 gallon tank was $80. So I opted for the bigger tank, but then I also had him add another 40' of drain line even though it's only a one bedroom.

 

[Pettrix]

I have a family member that had to undergo Chemo twice. The load on the septic system was not an issue. Since this is a new house you will have a 1.6 GPF toilet so unless the person is sick hundreds of times a day it is not going to bother the septic system, and frankly at the level of use, you have bigger problems than the septic system.


Figure out how much water you think you will use per day, then figure in your peak loads for holiday visits, then focus on the septic system size.

Later,
Dan

Thanks for the advice!

I was worried about the chemo and the septic system. Someone once told me that vomit destroys the septic tank because it kills the bacteria due to the content acidity and the undigested food which cannot breakdown as quickly in the septic tank like digested food can.

When the water loads were calculated for our home design, we were right around 1,500 GAL - 1,700 GAL but when I talked to the septic installer and the engineer, it seemed worth the extra $1k-$2k to get an up-sized system to handle larger loads. I do that with anything I do, I always go above the bare minimum because I learned early in life that it's cheaper to upgrade when building than to go back and fix it and upgrade later. For example, if code requires a 80 MPH wind load on the roof, I build the roof for a 110MPH wind load.

 

[Pettrix]

Pet, if you have the extra jingle in your pocket, go for it.
Here a 3br 2 ba system installed is under $3k and that is what I am putting in but I probably will add a few more sticks(20'ea) of drain line. Some up-sizing does make sense. For instance, when I had my shop/living quarter system put in 5 years ago my installer told me the difference in price from a 750 gallon to a 1,000 gallon tank was $80. So I opted for the bigger tank, but then I also had him add another 40' of drain line even though it's only a one bedroom.

It's worth it like you said. When the company is installing it, adding 40' of PVC drain line is easy and cheap. It's when you call them back a few years later when your system is having problems and you have to upgrade the lines that they charge you an arm and leg to do the work.

 

[lilranch2001]

I think this thread is full of chit.........

:laughing:

 

[boggen]

with bigger tank and bigger leach field. keep in mind that leach field piping is only a couple feet under the ground. and if you plan to do any land scaping work, or putting in a pool, or a rubber liner pond or like in the feature. the septic tank and leach field can take up a huge area. limiting your options of were to place things later down the road. or what you can drive over the area without fear or destroying your piping for the leach field. a leach field normally requires nothing be built over top of it. and that the grass be kept mowed with a finishing mower.

with above said, pending on your property / acreage and placement of house and shed/s. you may want to plan on some sort of drivable path along both sides of the house to get stuff back around it. with a tractor, or a truck fully loaded down with materials (lumbers, concrete, tractor, dirt, etc..) so you are not driving over top of the leach field.

you really can not add or remove dirt over a leach field once a leach field is put in, without effecting it. so any sort of major dirt work, you would most likely want done first, before digging holes and trenches to install the leach field.

keep in mind run off water from the roof / gutters, and divert all the water possible away from the leach field. and slop the land around leach field away from it. so run off water does not collect within the leach field.

p.s. it seems like everyone that has a leach field, you can notice were it is, when in drought season for the area, due to only spot grass is greener is, above the leach field! all other grass is brown and almost dead. all that fertilizer and water must be doing something!

===========
i never think about it any more (entire life on septic and leach field), but for newbies with a septic tank and leach field vs city sewer. you may want to begin getting into the hang of, selecting various cleaners you use. and how much you dump down the toliet or bath tub. when cleaning things and dumping the waste water. so do not take out your non aerobic bacteria in the septic tank and leach field. seen to many times folks like to "over dose" some sort of cleaner to really clean something, and just dump down a floor drain or toliet or bathtub drain. for a city this may be ok, but septic tank and leach field, it could be bad.

============
a septic tank and leach field. do not automatically and quickly take control of extra waste from say a large party, or family / friend visit for a extended week, holiday doing. it does take some time for the bacteria colonies to grow. and deal with waste as it comes in.

on other hand the water itself (not counting the waste in the water) from a large party or you dumping say an aquarium water down a drain for water changes for the aquarium. to large party to other. a larger leach field will help allow that water to disperse into the ground. BUT again if there is a lot more waste than what the septic tank and leach field is use to all of a sudden. you still may have problems. simply due to the bacteria coloneys, and ground/dirt around the leach field. is not use to drain that much water. and may take a tad longer for things to eventually catchup and grow and let the water disperse into the ground / dirt.

with above said, a larger septic tank and larger leach field can help. but after so much, the benefits become less and less. when you are barely putting a load on the septic tank and leach field. and when those holidays come up. you should plan ahead some. so you are not pushing things to a point of a possible failure / clog.

 

[Pettrix]

with bigger tank and bigger leach field. keep in mind that leach field piping is only a couple feet under the ground. and if you plan to do any land scaping work, or putting in a pool, or a rubber liner pond or like in the feature. the septic tank and leach field can take up a huge area. limiting your options of were to place things later down the road. or what you can drive over the area without fear or destroying your piping for the leach field. a leach field normally requires nothing be built over top of it. and that the grass be kept mowed with a finishing mower.

with above said, pending on your property / acreage and placement of house and shed/s. you may want to plan on some sort of drivable path along both sides of the house to get stuff back around it. with a tractor, or a truck fully loaded down with materials (lumbers, concrete, tractor, dirt, etc..) so you are not driving over top of the leach field.

The home site is on 15 acres, so leach field space is not a problem. Plus this is in Northern AZ, so NO grass to grow or mow. The ground is really dry. I planned the location of the home and leach field to be in such an area that nothing would be driven on it but if needed, one can drive around to the other side of it without disturbing the leach field.

keep in mind run off water from the roof / gutters, and divert all the water possible away from the leach field. and slop the land around leach field away from it. so run off water does not collect within the leach field.

The leach field is on a 2%-3% slope and it really starts to slope steeper further down so drainage and water collection on the field shouldn't be a problem.

i never think about it any more (entire life on septic and leach field), but for newbies with a septic tank and leach field vs city sewer. you may want to begin getting into the hang of, selecting various cleaners you use. and how much you dump down the toliet or bath tub. when cleaning things and dumping the waste water. so do not take out your non aerobic bacteria in the septic tank and leach field. seen to many times folks like to "over dose" some sort of cleaner to really clean something, and just dump down a floor drain or toliet or bathtub drain. for a city this may be ok, but septic tank and leach field, it could be bad.

Yep, we plan on getting rid of the Lysol Toilet Bowel Cleaner and replacing any and all cleaners with BAKING SODA. From what I read baking soda works well on cleaning stuff but it is safe on septics. Actually it supposedly helps with the breakdown of waste in the tank.

a septic tank and leach field. do not automatically and quickly take control of extra waste from say a large party, or family / friend visit for a extended week, holiday doing. it does take some time for the bacteria colonies to grow. and deal with waste as it comes in.

on other hand the water itself (not counting the waste in the water) from a large party or you dumping say an aquarium water down a drain for water changes for the aquarium. to large party to other. a larger leach field will help allow that water to disperse into the ground. BUT again if there is a lot more waste than what the septic tank and leach field is use to all of a sudden. you still may have problems. simply due to the bacteria coloneys, and ground/dirt around the leach field. is not use to drain that much water. and may take a tad longer for things to eventually catchup and grow and let the water disperse into the ground / dirt.

with above said, a larger septic tank and larger leach field can help. but after so much, the benefits become less and less. when you are barely putting a load on the septic tank and leach field. and when those holidays come up. you should plan ahead some. so you are not pushing things to a point of a possible failure / clog

I read that in large dosing loads, like that in a party or family visiting, adding some beneficial bacteria (the same stuff they use in waste water treatment plants), will help with dealing with those immediate large loads.

All-in-all the larger the tank and leach field, the less likelihood of encountering problems. Things that are engineered above and beyond the bare minimum will fair better than those that don't have that extra engineering in them.

 

[BoFuller]

Did you say you couldn't find fiberglass tanks? I'm in Northern Arizona and the guy who put my system in said he couldn't find concrete tanks. Everybody around here uses fiberglass.

 

[Pettrix]

Did you say you couldn't find fiberglass tanks? I'm in Northern Arizona and the guy who put my system in said he couldn't find concrete tanks. Everybody around here uses fiberglass.

I'm getting mine from Yavapai Pre-Cast out in Chino Valley, AZ. That's all they have and make out here is precast concrete.

Maybe they don't deliver out to Seligman? Those concrete tanks weigh 20,000 LBS.

Out here in Prescott, it's 95% concrete tanks. Fiberglass is rare.

 

[BoFuller]

Probably the shipping costs. I think you have it right.

 

[BoFuller]

I think you're smart to upsize. I'm doing a 1500 gallon for a 3 bedroom, but there is only the two of us.