[Yodaman]

I have a house that is in need of back flow prevention. When the storm drain floods the line backs up into the basement wash sink and also past the trap on the washer drain. No floor drains.

There is a 3" main line exiting horizontally right at basement floor level.
The washer drop and the wash sink tee are just a couple feet from the exit point.

I could put in a 3" main line backflow preventer at about $250. Would need to install horizontally. Or possibly considering 2 separate 2"check valves that I could install vertically that are only about $30 each.

The next higher drain is the first floor tub, but if we have water backing up that far we have far worse problems then then the drain.

Any thoughts?

 

[MrBryan]

I installed one of the mainline backwater valves in my home. I would highly recommend it. My neighborhood was build up in the late teens and into the 1920's and we have an old combined sewer system that tends to back up during periods of heavy rain.

It has successfully stopped water from backing up at least twice (that I know of) since the install.

 

[b-boy]

I have a similar situation. It's even worse, because I have a floor drain that's tied right into the main sewer line. There's not even a trap. Sewage percolates right into the basement. I have it plugged with a stopper to keep the sewage and the smell out.

I've asked several plumbers about a whole-house backflow unit, but they don't seem to want to install them.

Any idea why?

 

[MrBryan]

Probably because it is a huge PIA.

 

[Yodaman]

yea that pretty much answers b-boys question, the other option is to install it just outside the foundation wall which isn't really much easier.

My install could actually go above the floor and inside. My only question is should I just check a 2" line that will service the washer and a wash sink in lieu of the main line.

Originally I was thinking of using individual check valves for the washer and wash sink, but after looking at it closer I could just tie them together first with a single.

But not sure if check valves and backflow preventer are really the same animal. Price sure isn't

 

[MrBryan]

I liked this particular valve for several reasons. Above all else it came with an access hatch and it has a clear lid and removable clean out for easy servicing.

In this one the flapper is normally open, and it shuts only when a backup occurs. That is opposed to a normally closed design where the flapper only opens from the force of water flowing down the pipe, but remains closed the rest of the time.

Depending on the configuration of the DWV system and where the valve is placed, the normally closed design can cause venting issues because it doesn't allow air to move freely inside the pipe.

This one was a little pricey but worth every penny considering it protects the entire contents of my basement. Plus, a bad enough backup can take out a furnace, water heater, and washer/dryer too.

 

[TheEplumber]

The UPC is the code I plumb with. It states that only fixtures below the rim of the sewer manhole shall have backflow protection. So I would install the 2" valves- unless you have a floordrain too

 

[MrBryan]

The UPC is the code I plumb with. It states that only fixtures below the rim of the sewer manhole shall have backflow protection. So I would install the 2" valves- unless you have a floordrain too

Are you positive on that? My understanding of the code is that it allows you to place backflow prevention anywhere, and that fixtures below the level of the lowest manhole require backflow protection.

Regardless, try telling someone who has had sewage back up their basement floor drains that backflow protection on their home won't meet code because the elevation of their home isn't low enough.

 

[Yodaman]

I have no floor drains just the sink and washer extension. When the storm drain floods it wood back up into the wash sink. Nice aroma!
I am prepping the house for sale and this should be corrected.
Thanks Eplumb that route will save a few $

 

[TheEplumber]

Are you positive on that? My understanding of the code is that it allows you to place backflow prevention anywhere, and that fixtures below the level of the lowest manhole require backflow protection.

Regardless, try telling someone who has had sewage back up their basement floor drains that backflow protection on their home won't meet code because the elevation of their home isn't low enough.

UPC 710 describes when and when not to use a backwater valve

UPC 710.1 states "Fixtures on floor levels above such elevation shall not discharge through the backwater valve"
http://www.iapmo.org/California Plumbing Code/Chapter 07.pdf
This is my states code- IPC may read different.

Yodaman stated he has no floor drains, so no need to bust up the floor for a whole house backwater valve.

 

[MrBryan]

UPC 710 describes when and when not to use a backwater valve

UPC 710.1 states "Fixtures on floor levels above such elevation shall not discharge through the backwater valve"
http://www.iapmo.org/California Plumbing Code/Chapter 07.pdf
This is my states code- IPC may read different.

Yodaman stated he has no floor drains, so no need to bust up the floor for a whole house backwater valve.

Gotcha.
Agreed that a whole house valve in the floor would be overkill for yodaman.

Now I am curious about the verbiage in the code for my area - I will have to do some homework

 

[Ghostmaker]

Gotcha.
Agreed that a whole house valve in the floor would be overkill for yodaman.

Now I am curious about the verbiage in the code for my area - I will have to do some homework

IPC is the same in that regard.:devil3:

 

[WhatRnsdownhill]

I have no floor drains just the sink and washer extension. When the storm drain floods it wood back up into the wash sink. Nice aroma!
I am prepping the house for sale and this should be corrected.
Thanks Eplumb that route will save a few $

if your selling the house, I personally wouldnt install anything to grab the attention of a house inspector to tell the people buying the house you have issues with sewer backing up once in awhile...that could open a bucket of worms...and possibly kill a sale..

 

[Yodaman]

if your selling the house, I personally wouldnt install anything to grab the attention of a house inspector to tell the people buying the house you have issues with sewer backing up once in awhile...that could open a bucket of worms...and possibly kill a sale..

I wouldn't sleep at night, :wink2: Kidding aside, I am doing some other work in the area including moving the wash sink. Not really a big deal to add a check valve. The back ups were minor, amounting to maybe 12" of fluid in the deep sink that always drained off in about a hour and occurred on avg every 5 years. The check valve will remedy the problem altogether.

Would that deter you from buying the house of your dreams?

 

[jimn]

Depends what else is in the market. Certainly if I need to choose between two houses , one is acceptable and meets most of my requirements and the other is a better fit but has sewer back problems , I choose the first house. Rarely do plumbing problems improve on their own. A backflow valve in a house with city sewers would be a plus for me. After having my butt burned in the past, if I see any sign of recent changes that are not cosmetic in a potential buy, I march down to city hall and ask to see all the building and mechanical permits on a property. I won't say anything to the city if I see something amiss but I will walk away from the purchase.