3" or 4" PVC for septic

Farwell · May 10, 2006

Re: 3\" or 4\" PVC for septic

Steve,
It is much easier and quicker as well. You only have to glue 2 pieces at each joint rather than 4 and is less messy.
Farwell

srs · May 11, 2006

Re: 3\" or 4\" PVC for septic

rdln and farwell, thanks for the explanation. Sounds like the bell end is the way to go.

bebster · May 28, 2006

Re: 3\" or 4\" PVC for septic

The cost of 4" over 3" is so small that it's worth the extra insurance, especially if it's not accessible after building. When in doubt overbuild instead of underbuild -- that's my motto!

The local plumbing inspector just last week required my plumber to use 4" where it ran underground into the house. One argument is that even though there is just one bath on it now, you never know what might be added in the future.

bebster · May 28, 2006

Re: 3\" or 4\" PVC for septic

The cost of 4" over 3" is so small that it's worth the extra insurance, especially if it's not accessible after building. When in doubt overbuild instead of underbuild -- that's my motto!

The local plumbing inspector just last week required my plumber to use 4" where it ran underground into the house. One argument is that even though there is just one bath on it now, you never know what might be added in the future.

Sully2 · May 28, 2006

Re: 3\" or 4\" PVC for septic

All drain lines in my own home here are 2 inch ( regardless of tub or shower) running into 4 inch PVC. Finding connection pieces for 1 1/2 and 3 inch ..at times..can be a real BIT**. Can find 2" and 4" anywhere. Any interior walls that stacks..etc..run thru..are 2 x 6 walls..INSULATED...so there isnt any noise transmitted

Sully2 · May 28, 2006

Re: 3\" or 4\" PVC for septic

All drain lines in my own home here are 2 inch ( regardless of tub or shower) running into 4 inch PVC. Finding connection pieces for 1 1/2 and 3 inch ..at times..can be a real BIT**. Can find 2" and 4" anywhere. Any interior walls that stacks..etc..run thru..are 2 x 6 walls..INSULATED...so there isnt any noise transmitted

srs · May 28, 2006

Re: 3\" or 4\" PVC for septic

bebster and sully, thanks for your input. Underground I'll use 4" sewer line. I will not use 3". Thanks to everyone.

srs · May 28, 2006

Re: 3\" or 4\" PVC for septic

bebster and sully, thanks for your input. Underground I'll use 4" sewer line. I will not use 3". Thanks to everyone.

CurlyDave · May 29, 2006

Re: 3\" or 4\" PVC for septic

Any interior walls that stacks..etc..run thru..are 2 x 6 walls..INSULATED...so there isnt any noise transmitted

I insulated all my bathroom walls when I built the house, and wrapped insulation around every drain pipe. Then I tested it, especially the upstairs toilets. Even the slightest hint of rushing water and another layer went on.

I had a helper who really made a game out of it -- he would get in the bathroom then grunt & groan prodigously before he flushed the toilet. Not only did we silence the drain pipes, but the grunting & groaning convinced me to re-route a few air ducts, which can sometimes have a megaphone effect...

CurlyDave · May 29, 2006

Re: 3\" or 4\" PVC for septic

Any interior walls that stacks..etc..run thru..are 2 x 6 walls..INSULATED...so there isnt any noise transmitted

I insulated all my bathroom walls when I built the house, and wrapped insulation around every drain pipe. Then I tested it, especially the upstairs toilets. Even the slightest hint of rushing water and another layer went on.

I had a helper who really made a game out of it -- he would get in the bathroom then grunt & groan prodigously before he flushed the toilet. Not only did we silence the drain pipes, but the grunting & groaning convinced me to re-route a few air ducts, which can sometimes have a megaphone effect...

dbdartman · May 29, 2006

Re: 3\" or 4\" PVC for septic

Back in 1961, when we built our last house (in the suburbs), my father did ALL the plumbing. He was an old-timer (soil pipe & lead joints). The neighbor across the street asked if his soil pipe drain line should be 3" or 4", as he was considering the "bigger is better" route. My pop's justification for using 3" over 4" was that you would get a better "wash-out" with the 3" which would keep the top of the pipe cleaner, 4" would be more prone to corrosion along the top of the pipe. I witnessed this first hand about 25 years later (mid 80's) in a house a friend bought. We had to replace a couple sections of that rotted out along the top, in his approximately 50 year old drain.

Yea, I know, this doesn't apply to plastic vs. cast iron, but thought it might be worth considering (keep the inside of the line cleaner), or at least of slight interest to some of the old-timers.

BTW, we moved from that 1961 house 18 months ago & the 3" cast iron soil pipe was still in excellent (like new) condition. Current house is two manufactured ranch style connected & all drainage is plastic (4" sch40 main, one bath is almost 100 ft from the septic).

dbdartman · May 29, 2006

Re: 3\" or 4\" PVC for septic

Back in 1961, when we built our last house (in the suburbs), my father did ALL the plumbing. He was an old-timer (soil pipe & lead joints). The neighbor across the street asked if his soil pipe drain line should be 3" or 4", as he was considering the "bigger is better" route. My pop's justification for using 3" over 4" was that you would get a better "wash-out" with the 3" which would keep the top of the pipe cleaner, 4" would be more prone to corrosion along the top of the pipe. I witnessed this first hand about 25 years later (mid 80's) in a house a friend bought. We had to replace a couple sections of that rotted out along the top, in his approximately 50 year old drain.

Yea, I know, this doesn't apply to plastic vs. cast iron, but thought it might be worth considering (keep the inside of the line cleaner), or at least of slight interest to some of the old-timers.

BTW, we moved from that 1961 house 18 months ago & the 3" cast iron soil pipe was still in excellent (like new) condition. Current house is two manufactured ranch style connected & all drainage is plastic (4" sch40 main, one bath is almost 100 ft from the septic).

srs · May 30, 2006

Re: 3\" or 4\" PVC for septic

I was in the local Lowe's store and was checking out their sewer lines. Both were schedule 40, blue in color, one had a bell end which would be glued (I guess), and the other had a bell type end but with a rubber gasket inside. I gather with the gasket one you shove the male end into the female end and the gasket keeps everything tight. /forums/images/graemlins/smirk.gif Is one better than the other?

srs · May 30, 2006

Re: 3\" or 4\" PVC for septic

I was in the local Lowe's store and was checking out their sewer lines. Both were schedule 40, blue in color, one had a bell end which would be glued (I guess), and the other had a bell type end but with a rubber gasket inside. I gather with the gasket one you shove the male end into the female end and the gasket keeps everything tight. /forums/images/graemlins/smirk.gif Is one better than the other?

kennyd · May 30, 2006

Re: 3\" or 4\" PVC for septic

( I was in the local Lowe's store and was checking out their sewer lines. Both were schedule 40, blue in color )

Go check again...
The blue pipe should say "SDR 35" on it. It is usually used for irrigation or storm water drainage. The regular PVC fitting will not fit the blue pipe.

You can get regular 4" SH40 PVC, in 20' lengths, with the bell end at a plumbing supply house like Northeastern Supply. It is far better to use this underground for two main reasons...
1. 1/2 the # of joints compared to the 10' lengths the BigBox stores sell.
2. The bell end gives a joint overlap of about 6" or so, so you have a much stronger joint as opposed to using the regular couplers that only give about 2" overlap on each side of the joint.

Hope this helps...

kennyd · May 30, 2006

Re: 3\" or 4\" PVC for septic

( I was in the local Lowe's store and was checking out their sewer lines. Both were schedule 40, blue in color )

Go check again...
The blue pipe should say "SDR 35" on it. It is usually used for irrigation or storm water drainage. The regular PVC fitting will not fit the blue pipe.

You can get regular 4" SH40 PVC, in 20' lengths, with the bell end at a plumbing supply house like Northeastern Supply. It is far better to use this underground for two main reasons...
1. 1/2 the # of joints compared to the 10' lengths the BigBox stores sell.
2. The bell end gives a joint overlap of about 6" or so, so you have a much stronger joint as opposed to using the regular couplers that only give about 2" overlap on each side of the joint.

Hope this helps...

srs · May 31, 2006

Re: 3\" or 4\" PVC for septic

( ( I was in the local Lowe's store and was checking out their sewer lines. Both were schedule 40, blue in color )

Go check again...
The blue pipe should say "SDR 35" on it. )
Thanks Kenny. I'll double check when I go back to Lowe's and you're right about the longer pieces. I'll also check the supply houses. If I understand you correctly you're suggesting I go with the large bell type glued pipe vs. the one with the rubber gasket, (which is not glued), is that correct? Again thank you.

srs · May 31, 2006

Re: 3\" or 4\" PVC for septic

( ( I was in the local Lowe's store and was checking out their sewer lines. Both were schedule 40, blue in color )

Go check again...
The blue pipe should say "SDR 35" on it. )
Thanks Kenny. I'll double check when I go back to Lowe's and you're right about the longer pieces. I'll also check the supply houses. If I understand you correctly you're suggesting I go with the large bell type glued pipe vs. the one with the rubber gasket, (which is not glued), is that correct? Again thank you.

kennyd · May 31, 2006

Re: 3\" or 4\" PVC for septic

(
If I understand you correctly you're suggesting I go with the large bell type glued pipe vs. the one with the rubber gasket, (which is not glued), is that correct? Again thank you. )

Yes, glue type for sure for plumbing DWV (Drain,Waste & Vent).
The gasketed pipe is used mostly for storm drains.

kennyd · May 31, 2006

Re: 3\" or 4\" PVC for septic

(
If I understand you correctly you're suggesting I go with the large bell type glued pipe vs. the one with the rubber gasket, (which is not glued), is that correct? Again thank you. )

Yes, glue type for sure for plumbing DWV (Drain,Waste & Vent).
The gasketed pipe is used mostly for storm drains.