dbdartman
Gold Member
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).
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).
