Leaky laterals causing basement flooding?

[Phil Thien]

I thought I'd ask here. This doesn't make sense to me, maybe I'm wrong in my assumptions.

I live in a suburb of Milwaukee.

The last few big rains (more than an inch or two in a short amount of time), basements of homes in some areas have flooded. Not mine, thank God.

The water comes in through the floor drain, I've read. The last couple of years, there have been some real downpours with several inches of rain in an hour or so. "Hundred-year rains," but we've had a cluster of them in a year or two. Yet, we have had very heavy rains previously. But basements didn't flood then.

ANYHOW... some basements are flooding and people are plenty upset. Some of these people have lived here for decades and never experienced water backing up into their basements.

The municipality hired consultants, and they seem fixated on "leaky laterals," or the main drain line from the home to the street. The consultants insist that leaky laterals allow rain water to infiltrate the storm sewer system, which causes sewer backups into homes.

What I don't understand is how the problem can occur so quickly after the heavy rain starts. These leaky laterals are ten feet or more under ground.

It seems to me that it would take rain water some time to work 10' down into the soil, find the pipe, and make it into the system. Also, a lateral isn't going to collect water from THAT wide an area, THAT quickly, is it? Basements start flooding within just a few minutes of the very heavy rains starting, I believe.

I also don't understand why, when we have had very heavy rains previously, we didn't have this level of flooding. When we first moved-in 16+ years ago, there were some very heavy rains, and spotty basement flooding. But, to the best of my knowledge, the water came in from outside the home, not from the floor drains.

The consultants and the village make it seems like we have rivers running underground near the laterals. But, if that were the case, I'd expect to see sink holes resulting from erosion. And I'd expect the department of public works to be complaining of lots of soil in the sewers.

The suspicious side of me thinks there is a chance that some of the extensive sewer work in the last ten years may have been done improperly. Perhaps some pipes were undersized. Perhaps some pipes were improperly combined. Perhaps some joints were poorly fitted.

The village wants to inspect all the laterals and force anyone with any cracks to replace or line the lateral. At great expense. That suspicious side of me thinks the consultant wants to line the pockets of contractor friends.

I'm concerned that all this work will be done and basements will still flood.

I do know that simply installing a backflow preventer would stop the backing-up problem. Many houses have valves already. It seems making nearly everyone with the old clay tiles cough-up $6k is a great way to line the pockets of contractors when adding a backflor preventor is less expensive and a guaranteed fix (compared to fixing laterals).

Any thoughts?

Anyone go through anything like this in your own neck of the woods?

[JohnT Fitzgerald]

Phil, I am by no means trained or experienced on this topic - but I did read an article a while ago about how sinkholes are formed. If there are "leaky laterals" then water would not be the only thing making it's way into and down the pipes - also surrounding sediment and soil. This could gradually open up easier channels for surface water to make it down to the pipes. You might think it's 10' of solid ground, but it just might not be.

[Dan Hintz]

Ignore the man behind the curtain!




Someone is floating smoke to hide the fact that they don't yet know the cause... leaky laterals, as you said, could not only never flood that fast without a direct route to the water, and think of how much water would have to literally stuff them before the main couldn't handle it and it backed up into the smaller drains. It no make sense, Dr. Jones!

[Lee Schierer]

Most likely the cause is outdated or clogged storm sewers that were not designed for the amount of water they are now handling. It is a common occurrence now that northern climates area getting more severe rain showers. Older homes were typically connected directly to storm sewers without benefit of back flow prevention valves. They are pretty cheap insurance if installed when the home was constructed, but are more costly now that all the landscaping is done since you have to dig and possibly break up the floor in the house.

[Phil Thien]

Ignore the man behind the curtain!

Someone is floating smoke to hide the fact that they don't yet know the cause... leaky laterals, as you said, could not only never flood that fast without a direct route to the water, and think of how much water would have to literally stuff them before the main couldn't handle it and it backed up into the smaller drains. It no make sense, Dr. Jones!

The "consultant" recently said every single lateral needs to be inspected (at a cost), and any any sort of problems identified need to be fixed (fixing can run about $6000 per).

So the village hired the consultant to inspect every lateral (at a cost, of course).

That seems best-case for the consultant. That is a lot of work, resulting in a lot of income.

I cannot discount the possibility that the consultant is best friends with all the areas contractors that perform lateral repairs, either. You like to think the best of people, but so often you discover the worst.

I also cannot discount the chance that village hall is pressing the consultant in this direction because they want to conceal the true problem (for instance, sewer work that was performed incorrectly and was possible known of by people at village hall).

The fact is, the village right to our south has COMBINED sanitary and rain lines. So it seems possible, to me, that if there is very heavy rain, they could saturate their lines in little time. I am not familiar with how sewer lines are handled where one community ends and another begins. I suppose the systems could be entirely separate. Somehow, though, I suspect that isn't always the case.

So I thought I'd ask here before I become more involved by attending meetings and communicating (with village hall and my neighbors) my concerns about the direction of the work.

[Phil Thien]

Most likely the cause is outdated or clogged storm sewers that were not designed for the amount of water they are now handling. It is a common occurrence now that northern climates area getting more severe rain showers. Older homes were typically connected directly to storm sewers without benefit of back flow prevention valves. They are pretty cheap insurance if installed when the home was constructed, but are more costly now that all the landscaping is done since you have to dig and possibly break up the floor in the house.

To my way of thinking, no amount of rain should cause a sanitary backup in your basement unless there is water infiltration from somewhere.

The first thought this consultant had was that people had weeping and gutter systems illegally connected to sanitary systems.

And they found some. Some houses apparently have gutters feeding the sanitary sewers. And that still has not been fully corrected. Perhaps I have been too lax in not attending the meetings. But it seems to me that once you have identified several people pouring that much water into the sanitary system, you don't go any further until that is corrected.

Apparently some people are arguing that they cannot disconnect the rain water from their sanitary easily. And, that their houses are 75 years old, their downspouts always emptied into sanitary lines, and there was never before a problem.

The "never before a problem" doesn't fall on deaf ears for me. I'm very open to that argument. These homeowners are saying "look elsewhere, my configuration hasn't changed in 75 years." Now, I suppose it is possible that sanitary sewer lines were replaced with smaller ones that can no longer handle that load. And I suppose the people that called for smaller lines may not have been aware of some older homes pouring that much water into the sanitary lines. And if that is the case, those houses should be forced to disconnect, or be responsible for any damage. OTOH, if sewers have been replaced and the sizes have not changed, then the problem is elsewhere (if there was no problem with a 2" rainfall ten years ago, and there is one today, the problem MUST be elsewhere).

It just seems to me that you go after the largest contributors of rain water first.

It wouldn't seem to be leaky laterals to me.

I still believe something is configured incorrectly, or newer pipes are smaller than older pipes and we have to make adjustments.

I'm on the edge of the village, and I'm on the largest street. The sewer deep under our street is called the Hampton Express. I don't know the size, but it is apparently BIG (when they name a sewer line, it is probably pretty big) and feeds directly into the "deep tunnel" (another boondoggle). I'm pretty sure I could empty an Olympic pool into a 6" line during the heaviest rain storm w/o causing any problems.

But I am concerned that some joker is going to say I need to fix this, or fix that, just to line the pockets of his contractor friends. So I'm trying to get in front of this.

[Ken Fitzgerald]

Phil,
If the storm water and the sewer system are interconnected and the problem only happens when it storms, I would suggest that Lee is correct.

The number of homes being serviced by the existing system has outgrown the carrying capacity of the system or it's damaged and not handling the increased amount of water during the storms.

It would be very reasonable to think that as a suburb grew, more homes were added to the existing sewer systems and more street drains to handle the water in these same areas. All it would take would be one miscalculation or failure to take this into consideration and all future calculations would be in error too as the community continues to grow.

Adding the back flow preventer would protect ones home but it makes the problem worse for the guy who doesn't have one as the relief for the water has one less outlet.

[Lee Schierer]

Many older cities used storm sewers and sanitary as the same system and it is common for heavy rainfall to cause problems. That used to be the case in a couple of city/towns near me. People connected their basement drains to the sewer system and then connected their downspouts into their weeping system. Eventually they overwhelm the street drains and people end up with water in their basements coming up the floor drains during extra heavy rain periods. The only way to protect homes is to install back flow preventers in the connection to the sewers and not have downspouts connected to sanitary systems. Our local municipalities put smoke generators on the sanitary systems and then observed where smoke was coming out of downspouts. Illegal connections were then identified and given a fixed time limit to fix the problem before fines were levied. The fact that a home is 75+ years old had no bearing on the problem, some homes were over 100 years old.

[ray hampton]

To my way of thinking, no amount of rain should cause a sanitary backup in your basement unless there is water infiltration from somewhere.

The first thought this consultant had was that people had weeping and gutter systems illegally connected to sanitary systems.

And they found some. Some houses apparently have gutters feeding the sanitary sewers. And that still has not been fully corrected. Perhaps I have been too lax in not attending the meetings. But it seems to me that once you have identified several people pouring that much water into the sanitary system, you don't go any further until that is corrected.

Apparently some people are arguing that they cannot disconnect the rain water from their sanitary easily. And, that their houses are 75 years old, their downspouts always emptied into sanitary lines, and there was never before a problem.

The "never before a problem" doesn't fall on deaf ears for me. I'm very open to that argument. These homeowners are saying "look elsewhere, my configuration hasn't changed in 75 years." Now, I suppose it is possible that sanitary sewer lines were replaced with smaller ones that can no longer handle that load. And I suppose the people that called for smaller lines may not have been aware of some older homes pouring that much water into the sanitary lines. And if that is the case, those houses should be forced to disconnect, or be responsible for any damage. OTOH, if sewers have been replaced and the sizes have not changed, then the problem is elsewhere (if there was no problem with a 2" rainfall ten years ago, and there is one today, the problem MUST be elsewhere).

It just seems to me that you go after the largest contributors of rain water first.

It wouldn't seem to be leaky laterals to me.

I still believe something is configured incorrectly, or newer pipes are smaller than older pipes and we have to make adjustments.

I'm on the edge of the village, and I'm on the largest street. The sewer deep under our street is called the Hampton Express. I don't know the size, but it is apparently BIG (when they name a sewer line, it is probably pretty big) and feeds directly into the "deep tunnel" (another boondoggle). I'm pretty sure I could empty an Olympic pool into a 6" line during the heaviest rain storm w/o causing any problems.

But I am concerned that some joker is going to say I need to fix this, or fix that, just to line the pockets of his contractor friends. So I'm trying to get in front of this.

I vote for a stop up pipe or partly blockage
what is the deal with the "Hampton Express ?
I saw water backup shoot 20 feet high out of a flood drain and all punch presses and other machines got shut-down and everybody got to work at pushing the water back into the drain

[Phil Thien]

Many older cities used storm sewers and sanitary as the same system and it is common for heavy rainfall to cause problems. That used to be the case in a couple of city/towns near me. People connected their basement drains to the sewer system and then connected their downspouts into their weeping system. Eventually they overwhelm the street drains and people end up with water in their basements coming up the floor drains during extra heavy rain periods. The only way to protect homes is to install back flow preventers in the connection to the sewers and not have downspouts connected to sanitary systems. Our local municipalities put smoke generators on the sanitary systems and then observed where smoke was coming out of downspouts. Illegal connections were then identified and given a fixed time limit to fix the problem before fines were levied. The fact that a home is 75+ years old had no bearing on the problem, some homes were over 100 years old.

I agree that the age of the home has no bearing.

And I agree with the steps you've outlined.

The village has done the smoke tests. They've identified houses w/ illegal connections. Most people have apparently corrected those issues, a few are fighting it I believe (on the basis that it has always been like that and never was a problem, and their particular reconfigurations are going to be very costly).

The village has gone from having few (if any) backups just ten years ago to having backups (in some cases) with less than an inch of rain (if it comes fast enough). It is always the same homes.

And the problems continue after the smoke tests and subsequent repairs.

So now the new consultant says "leaky laterals" and I'm calling you know what on that.

It seems, in the world of "likely scenarios," that this consultant has focused or what I think is a particularly unlikely one.

The odds of this being caused by a bunch of laterals that have all become very leaky in the last five or so years don't seem that great to me. Especially compared to the chances of one or more serious engineering or construction mistakes being made during all the sewer work they've done over the same time period.

The more I think about it, the more I'm thinking we need to find a new consultant that is perhaps better skilled at critical thinking and problem solving.

If you just changed the oil in your car and notice the next day it is a quart low, you don't start thinking your engine is burning oil fast. You check for a tight filter and drain plug, right?

[Phil Thien]

Phil,
If the storm water and the sewer system are interconnected and the problem only happens when it storms, I would suggest that Lee is correct.

The number of homes being serviced by the existing system has outgrown the carrying capacity of the system or it's damaged and not handling the increased amount of water during the storms.

It would be very reasonable to think that as a suburb grew, more homes were added to the existing sewer systems and more street drains to handle the water in these same areas. All it would take would be one miscalculation or failure to take this into consideration and all future calculations would be in error too as the community continues to grow.

Adding the back flow preventer would protect ones home but it makes the problem worse for the guy who doesn't have one as the relief for the water has one less outlet.

Agree w/ everything you said.

The systems aren't supposed to be interconnected in OUR village. But of course, if they are interconnected in an adjoining village, how isolated are they for us, right? Perhaps they are completely separate, perhaps not. I do know one area experiencing problems is right on the line w/ the village w/ shared systems.

I can tell you that we are land-locked. No new construction for probably about forty years. This is an OLD suburb.

I agree, too, that adding backflow preventers may cause some homes without them to have gushers in their basements. LOL, that would suck.

I think about 75% of the problem is that the guys doing this work are all too young. Not enough experience.

[Phil Thien]

I vote for a stop up pipe or partly blockage
what is the deal with the "Hampton Express ?
I saw water backup shoot 20 feet high out of a flood drain and all punch presses and other machines got shut-down and everybody got to work at pushing the water back into the drain

The Hampton Express is BIG. I will try to find the size. I imagine it is a 24" or 36" sanitary sewer. It isn't clogging.

But one of the smaller mains could.

The village does a pretty good job inspecting them, though.

If I had to guess the problem, I'd guess that, during one or two of the construction projects, a confused team cross-connected one or more smaller storm lines to sanitary lines. Or removed large backflow preventers they didn't think were necessary, or for which they didn't have replacements that were compatible with the PVC they were using.

They have tested with dye. But they are assuming they know all the inlets for storm water. I imagine there are some they don't know about.

If it were me, I'd go back project by project, in chronological order, to before the problem surfaced. Examine each completed project with scrutiny. Find old engineering documents and compare what was there, to what is there now.

And if possible, I'd find some old timers that worked for the department of public works 15+ years ago and ask them if they'd like $20k to come back for fifteen days (all expenses paid) and just take a look at the problem. Maybe we'd have to fly them in from Arizona, Florida, or California. It would be worth it. When they were here, we didn't have these problems. Maybe they'd know why we're having them now.

[ray hampton]

Phil, I agree about hiring the old hands for a week or 2
are your town pipes made out of wood by any change ?
I do not recall the correct details but a town in Ohio had problems with their pipes, the gas pipes run thru. the plumbing pipes [ I hope that the gas pipe run thru. the sewage drain ]not the water main, running a gas pipe thru. a water pipe will heat the water

[Phil Thien]

Phil, I agree about hiring the old hands for a week or 2
are your town pipes made out of wood by any change ?
I do not recall the correct details but a town in Ohio had problems with their pipes, the gas pipes run thru. the plumbing pipes [ I hope that the gas pipe run thru. the sewage drain ]not the water main, running a gas pipe thru. a water pipe will heat the water

The new stuff is PVC, the old stuff they have been replacing is (I believe) concrete.

When they replace the mains in the streets, I do not notice them actually removing the old stuff. I'm not sure if they break it up and leave it in the ground, or if they run the new pipes inside the old, or what. I'm afraid I have not paid close enough attention.

[Dan Hintz]

Filling of the laterals is easy enough to check, and it doesn't require a $6000/per issue with the board, either. Hang a cup a few inches from the ceiling of any laterals in question and wait for a rain. If the cup is filled, the lateral is getting overwhelmed. I figure it'll cost you about $3 in dixie cups and $5 in wire hangers from the local drycleaners. It's not high-falutin', but it'll sure do the job as well as any inspection. No point spending thousands of man hours looking for cracks/blockages if the tubes just aren't getting filled.