Palo Alto officials are taking a new look at procedures that have produced erupting toilets, after recent incidents around town created both a messy bathroom and a messy political situation.
The most recent incident occurred Aug. 31 at the Chimalus Drive home of Richard Placone, a longtime observer and occasional harsh critic of city operations. Two earlier incidents were reported in the past three months, both reportedly relating to sewer work being done nearby.
"My 9-year-old granddaughter was just finishing her shower when suddenly the toilet erupted over 3 feet into the air, spraying raw sewage over the walls, sink, garden window, shower glass walls and the floor," Placone wrote in a Sept. 3 post-cleanup letter to City Manager Frank Benest, with copies to City Council members. (Placone told the Weekly the cleanup cost him about $2,000 and that the city indicated it would reimburse him.)
"She ran screaming from the bathroom calling for her grandmother. When Jeanne arrived at the bathroom, she was able to grab enough towels to keep the flood from flowing into the hall and ruining the carpet," Placone continued.
"She then went outside to confront the City of Palo Alto Utility Department workmen, who had been working on the sewer main since early morning.
"When she explained what was happening, she was told, somewhat dismissively, that they were using pressure to unblock the main line and sometimes this resulted in a back flow into a nearby home," Placone wrote.
He prefaced his complaint with a reference to modern literature: "If you have read the Harry Potter books you will be familiar with the wizard mischief of placing a jinx on a Muggle (non-magical person) toilet so that it flushes in reverse, i.e., becomes a regurgitating toilet."
"Can you imagine, Mr. Benest, the scare this gave to my granddaughter? Can you imagine the fright if someone was actually using the toilet when this eruption occurred?"
Utilities Director Valerie Fong said Thursday she is preparing a response to Placone's complaint, and "feels very badly" about the incident.
"Nobody should have to deal with that," she said, adding that there have been problems in that area before. She said the city is now sending video equipment on a small robot into the lines for a visual inspection, and that utilities operations and engineering people are working together to resolve the problem. She said she hopes the video survey and analysis of the video will be completed within a week.
It could mean repairing or even replacing the sewer main, she said.
The department also has launched a home-by-home survey of houses to make sure everyone has a cleanout in the line -- which she said Placone's home lacked -- that would allow any excess pressure in the lines to be released outside.
Placone said when his "steaming" wife reported her conversation with the crew to him he went out to question the workmen.
"They explained that they had inserted a pressure device into the main line and when the pressure was released it must have backed up into our bathroom.
"This happens, I was told, but this time not so dismissively."
But Placone said the eruption was only the first half of the problem.
"Soon (Wastewater) Supervisor Frank Alvarado came to the house and inspected the bathroom. He told me to call the city and they would arrange to have a cleanup crew come and clean up and make repairs to the damage.
"I asked why we were not informed in advance that such an event might occur so that the toilet could have been closed and sealed. He had no answer to this.
"He did say that there should be a safety valve located near our house and since one was not there he would see to it that one was installed. Our sewer line empties into the main right where the manhole cover is, so it would be the one to experience back pressure."
Placone said he immediately called the city manager's office, "since in my past experience Emily Harrison is the only one who seems able to get some action in an emergency like this." But Harrison was in a meeting, Benest was not in the office, and the woman who answered referred Placone to an administrative assistant.
"After I explained the problem to her, she said she would transfer me to a person who would arrange for Roto-Rooter to come and address the problem. I told her a blocked sewer was not the problem, at least not my sewer, but she said the company also did this kind of cleanup work.
"She then transferred the call and another woman answered, to whom I again explained the problem. She didn't know what I was talking about as she turned out to be the city's dispatcher. She said she would transfer me to Utility Department operations.
"The woman who then answered the phone listened to my problem, but when I asked her to please arrange that the cleanup company come at once to clean up the mess, she said that it was not in the city's protocol to do such things. This was something I would have to do, and then I could file a claim with the city attorney.
"When I told her that the city manager's office told me she would take care of it she said that 'they' didn't know what they were talking about, that this was not in the protocol of the Utility Department. I told her I had no idea whom to call and she suggested the Yellow Pages."
Placone then summarized with an overall assessment of apparent management failures within the city:
"Excuse me, but I am now convinced that you and your management staff, with the possible exception of Emily Harrison, have no idea how to manage this city, and the proof can be seen in the deteriorating infrastructure, the ongoing deficits, the scandal-ridden and inept Utility Department and the cavalier attitude of some city staff when confronted with a citizen who needs urgent help," he summed up.
Benest is out of town at a League of California Cities meeting and could not be reached for comment.
Comments
Old Palo Alto
on Sep 6, 2007 at 9:22 pm
on Sep 6, 2007 at 9:22 pm
Editor,
Thank you for that uplifting story!
The city needs some seriously funny news that we can all agree on.
Ventura
on Sep 6, 2007 at 10:42 pm
on Sep 6, 2007 at 10:42 pm
interesting story,
but it doesn't sound too funny to me,
and i like to laugh-
some heads should roll for this crap!
Embarcadero Oaks/Leland
on Sep 6, 2007 at 10:55 pm
on Sep 6, 2007 at 10:55 pm
The crap did not hit the roof yet. When it does, we will fire Frank Benest...
Next time, please make sure you keep someone from our family to guard the toilet seat. A seat not occupied is not a seat, it is a crap shoot...
Midtown
on Sep 7, 2007 at 5:01 am
on Sep 7, 2007 at 5:01 am
A while ago as the council was considering an increase in the travel budget I suggested, instead, that the money go toward building a teleconferencing room and that the city withdraw from any organization that did not have teleconference availability of conferences. I believe this is just one more example of the foolishness of paying top dollar for absentee managment.
Palo Verde
on Sep 7, 2007 at 7:41 am
on Sep 7, 2007 at 7:41 am
Excuse me, Richard, for saying this, but having "the exploding toilet" happen to you may turn out to be a blessing in disguise for our community.
You are a thoughtful, thorough person. When you asked for City help, you took notes and names. The point that comes through to me from the Weekly report, is not that a potentially preventable problem occurred, it is what happened next...how the employees of our City handled this messy situation.
Not at all well, so far.
This is what quality management is all about. Our City is close; by-in-large, we have quality people on the payroll. Now we need quality training to get each City employee to feel empowered to respond with thoughtful caring when the inevitable problem occurs.
Page One of the Training Manual: Pretend you worked for the City Utility and this happened to your mother. What would you do? OK, now do that for Richard Placone and his family.
After all, if solving unusual problems like this isn't in your job description, what are we paying you for?
Another Palo Alto neighborhood
on Sep 7, 2007 at 9:18 am
on Sep 7, 2007 at 9:18 am
Wow, see what reading Harry Potter can do for you!!!
Duveneck/St. Francis
on Sep 7, 2007 at 9:53 am
on Sep 7, 2007 at 9:53 am
This isn't funny at all - we probably came close to having the same thing happen a couple of years ago when a city subcontractor work truck was on our street. Some homeowners were at work so may have been unaware of what was going on. There was no advance notification, but apparently the crew were working on a sewer line running down the middle of the street. Our home is quite new, I doubt there is a deficiency on our property in terms of lines. I was home and noticed strong, weird plumbing sounds and found the water in our toilets to be splashing madly, starting to actually shoot out, so I closed the bowl lids, put towels nearby, and - having noticed the work truck nearby - ran outside to ask the workmen what they were doing. They acted casual, indicated they were doing sewer work, said they were doing routine maintenance work. They did not change their work in response to my concerns, though seemed to indicated it was related. I called the city, didn't get a real reaction, but as I say, I was highly concerned I was going to have real damage in my home. it was a close call.
Barron Park
on Sep 7, 2007 at 10:22 am
on Sep 7, 2007 at 10:22 am
This must have been what happened to me. I check my cleanout about every two months and I saw that it had back up into the backyard. I called RotoRooter and for about $250 they cleaned out my cleanout. They did not find a blockage and now I understand why. But still it cost me because I was not notified by the city that this could happen.
Barron Park
on Sep 7, 2007 at 10:58 am
on Sep 7, 2007 at 10:58 am
Thanks for the comments of concern re my regurgitating toilet. We are now back to normal, after an expenditure of $1567, which the city says it will repay me. It could have been worse as one of you noted, in that we were home,though within a half hour of leaving for the day. Had we come home and found the mess we would not have nesessarily known how high the eruption was, and theflood wouldhave flowed into thehallway, ruining carpets. The damage costs would have been significantly higher. I hope this has the effect of getting some management improvement. So far, not a single response from any one of the council members, who were copied with my letter to Mr. Benest, who has written a letter of apology, by the way.
Richard Placone
Evergreen Park
on Sep 7, 2007 at 12:21 pm
on Sep 7, 2007 at 12:21 pm
I had the same thing happen at my place, but the price tag was a bit less. What a mess!! It took about two days to clean up.
The city was responsive, to the point of being indulgent. Everyone was helpful, all the way to those in the atoorney's office, to help me file a claim.
I didn't mind calling the plumber, nor did I call anyone to clean the mess up. I cleaned it up myself, and billed the city a nominal charge for my labor.
What I fail to understand is why Mr. Placone shuold expect a call from a City Council member, or even a letter of apology from Frank Benest.
Yes, Mr. Placone was inconvenienced, and yes, he was inconvenienced by a flaw in sewage flow that couldn't be anticipated.
Things happen; I've never known anyone who WANTS to do a bad job.[Portion removed by Palo Alto Online staff.]
The people who run our city are PEOPLE, who occasionally, like the rest of us, make mistakes. Please treat them as such.
Midtown
on Sep 7, 2007 at 1:10 pm
on Sep 7, 2007 at 1:10 pm
Mr. Placone explained the reason for his distress. The failure of City Hall to properly route and handle his complaint on one phone call is a management problem. Absentee management has left its mark on the city. When will we learn?
College Terrace
on Sep 7, 2007 at 2:43 pm
on Sep 7, 2007 at 2:43 pm
Gee, Walter, you make it sound as if management is living in Panama. "Absentee management"? Another Wallisian exaggeration, I'm afraid.
It remains that "things happen", and nobody is perfect - not even Mr. Placone. Sometimes procedures are not optimal; that doesn't make the persons who engage those non-optimal procedures incompetent persons.
Mr. Placone might best cut the city some slack. His bathroom is probably cleaner now, than it ever was. So, there's a benefit, right there. :)
another community
on Sep 7, 2007 at 4:15 pm
on Sep 7, 2007 at 4:15 pm
This is not the first time this has happened. Many years ago on Old Adobe rd. It was Christmas when the sewer backed up into the home of a palo alto resident. The Fire Department spent the whole day there, Removing human waste from this persons home. Think they would be able to fix something in this town. Get a job in upper management for the City,Get a nice pay check, Never go into work for the citizens that pay you.Spend there money going to classes and padding your resume. Have to leave before things get to hot and get a better job someplace different. Makeing more money for they thing you did such a good jod for the Citizens of Palo Alto. [Portion removed by Palo Alto Online]
College Terrace
on Sep 7, 2007 at 4:46 pm
on Sep 7, 2007 at 4:46 pm
What's the ratio of successful flushes to full out explosions? Hmmm
Let's see: about 60,000 Palo Altans (not including day workers). Let's say four flushes per day, per person. That's 240,000 flushes per day (not including day workers, restaurant flushes, etc. etc.. Let's add another 60,000 flushes (conservative) per day for that.
so, 300k flushes per day x 365 days = 109 Million flushes per year (probably a gross underestimate)
Let's assume 50 explosions per year (which is probably off the charts; it's most likely more like 10-20 per year. Let's be generous and say 50 per year.
that = .00000046% "error rate"
Not bad! far better than six sigma - in fact, Palo Alto's untility qualigies for Six Sigma certifcation.
Mr. Placome, Walter, The Shadow: are any of yuor performances on the jon better than that?
College Terrace
on Sep 7, 2007 at 4:47 pm
on Sep 7, 2007 at 4:47 pm
oops! I mean "job" - above, in the last line - wow, talk about Freudian slips!!!! :)
Barron Park
on Sep 7, 2007 at 4:57 pm
on Sep 7, 2007 at 4:57 pm
Mike, what a strange analysis. (Love the typo, though - very funny!) The ratio of 'total flushes' to 'explosions' doesn't make much sense. Try 'total number of times sewers are worked on' to 'explosions'. Do you think we'd still be six sigma?
College Terrace
on Sep 7, 2007 at 5:17 pm
on Sep 7, 2007 at 5:17 pm
Boom!, you have just given the word "boom" a hole (sic0 new meaning. Isn't scatological banter fun?
Anyhoo, you do have a point, but lost in your point is the fact that toilets around here don't explode very often (go boom in the night? :)))
Mr. Placone has a reason to be upset, but little reason to be upset at anything other than fate. Sometimes, bad things happen to good toilets.
Duveneck/St. Francis
on Sep 7, 2007 at 5:19 pm
on Sep 7, 2007 at 5:19 pm
I thought Palo Alto was a nuclear free zone.
The Greenhouse
on Sep 7, 2007 at 5:39 pm
on Sep 7, 2007 at 5:39 pm
There is something about toilets that makes macho men go into paroxysms of anxiety.
Maybe if they were the major responsible person for babies food and diapers and laundry and other unglamorous tasks, they wouldn't feel the need to make so many nervous foolish jokes.
Barron Park
on Sep 7, 2007 at 6:40 pm
on Sep 7, 2007 at 6:40 pm
Maybe if they closed the cover they wouldn't be so nervous.
Midtown
on Sep 7, 2007 at 7:20 pm
on Sep 7, 2007 at 7:20 pm
The correct procedure for this process is:
1. Install a transfer pump to send sewerage beyond the stoppage
2. Notify all homeowners on the affected section to not flush. Turn off their water if need be.
3. Install a pneumatic stopper in each lateral, installing a cleanout if this is not there.
4. purge sewer. Never use a pressure purge when there is the possibility of a backup. Cleanup of a sewerage spill into a residence is not a janitorial job, it is a removal of contaminated material, sanitizing and then restoration. Done correctly it is not cheap.
5. remove all pneumatic stoppers and inform residents the sewer is back on line.
I have always questioned the value to the city of sending management to all the out of town meetings. I have recommended an alternative, the teleconference.
I also believe that whenever a city representative is contacted about a possible city liability the last thing they should be told is to fix it and sue. I would, in fact, consider that advice a cause for seperation of the worker making such a statement and retraining of the superior. While it may be cute to say that "it" don't flow uphill and payday's Friday, Sanitary works and water purification have benefitted society far more than all the medical profession put together. Management of those functions must become before green and pinko excursions.
Midtown
on Sep 7, 2007 at 10:05 pm
on Sep 7, 2007 at 10:05 pm
It would be very interesting to know how often this happens. It seems it’s not unusual, which makes me wonder why the city isn’t more concerned about it (hazardous waste dangers, cleanup costs, potential lawsuits). Environmental issues are high on our mayor’s priority list. Or does a home not qualify as part of the city’s environment?
In June, our neighbor – an elderly widow – heard what sounded like an explosion in her house. Both of her bathrooms were covered in filthy water and the standing water extended out into the hallway and bedroom, soaking the carpets.
The cause was city workers "blowing out the sewers" a couple of blocks away.
She and another neighbor (also elderly widow) walked over to the city workers, who gave a number to call at Waste Management. She was told, "we have a procedure for this" (so it’s not an unusual occurrence) and she was asked to find out if her insurance would cover it! She was also told that the house across the street might have the same problem and she should contact her neighbors.
The form she was asked to fill out asks for the names of the employees working on the sewers and the license number of their truck. Wouldn't the city have that information?
A man came out to take photos, told her not to touch anything because it was hazardous waste, and gave her a number for a cleaning service. The service came out, tore out the linoleum in the bathrooms, tore out wallboard, took all her towels and bathmats, measured how far into the hall and bedroom the water had gone. They sprayed disinfectant all over, which was still wet a week later. They also put in dehumidifiers.
About 10 days later, the dehumidifiers were still noisily running, her toilet was in her bathtub, and she was using the facilities at a neighbor’s house.
Barron Park
on Sep 7, 2007 at 11:20 pm
on Sep 7, 2007 at 11:20 pm
Mike. I don't think this was fate. It seems to occur too often according to the stories. The Utility Dept. should have a procedure in place to deal with this problem. Apparently it doesn't or not all employees know of it. More training!!
Mr. Wallis describes a way of avoiding the problem which is cheaper than the city paying to clean up messes. But you don't know how many houses would need to be included if you consider Pat's story about the work occurring two blocks away.
I think the "paroxysms of anxiety" are a nervous relief reaction that "there but for the grace of God go I".
Charleston Meadows
on Sep 8, 2007 at 3:31 am
on Sep 8, 2007 at 3:31 am
Thank God I've moved. [Portion removed by Palo Alto Online staff.]
Midtown
on Sep 8, 2007 at 7:19 am
on Sep 8, 2007 at 7:19 am
Management.
Downtown North
on Sep 8, 2007 at 10:28 am
on Sep 8, 2007 at 10:28 am
When occurance like these are not really of any surprise or concern - you know we have crossed a boundary - we have been equated to the filth of the toilet.
Another Palo Alto neighborhood
on Sep 8, 2007 at 12:19 pm
on Sep 8, 2007 at 12:19 pm
Mr Placone,
This is egregious to happen even to one resident. I am appalled that this has happened to so many others, and the city has made no apparent attempt to prevent further incidents. Given all the incidents already, the city should at least have had an efficient response in your case. Apologies do matter, because they require thought. Good for Benest's office for offering a sincere one.
Thanks for posting and making us all aware of it. Sorry you had to deal with so many jerks on Town Square. We can only hope it happens to them a few times so they have something more productive to do with their time.
I hope everyone reading this will consider how happy you would be to have to clean up raw sewage spewing in your home, around your babies or children, and the nightmare of having to deal with it while you are dealing with everything else in your lives. Call the city and demand they figure out how to prevent this from happening ever again. These things persist because people don't bother to complain. (Well, and because of poor management, but that's something to consider on election day.)
Midtown
on Sep 8, 2007 at 12:57 pm
on Sep 8, 2007 at 12:57 pm
After the mostly absentee management of our previous Utility Director I had high hopes that replacing him with an honest to God Professional Engineer would see a return to engineering principles in the operaton of that department. Alas, they are still hung up on the stupid green program.
As much as I hate outside consultants I believe it is time to do a general management audit of the city, to see what is necessary to make them mind the store. The primary correction must be a reappraisal of the appropriate functions of city government.
I suggested years ago that Palo Alto might more appropriately become a Municipal Service District with specifically delineated responsibilities. You can't trust the kids with the keys.
another community
on Sep 8, 2007 at 4:27 pm
on Sep 8, 2007 at 4:27 pm
[Post removed by Palo Alto Online staff.]
Barron Park
on Sep 8, 2007 at 6:54 pm
on Sep 8, 2007 at 6:54 pm
I'd like to make one thing perfectly clear: Cleaning up a mess like this is NOT a housekeeping matter. The sewer line contains toxins and deadly bacteria. In our case, Jeanne has a surgical implant that is susceptible to life threatening infection. She even has to take special antibiotics just to have routine dental work. So this bathroom has to be toxin and bacteria free. Anyone who tries to clean up the mess is taking a serious risk. The professional cleanup people wore protective clothes, latex gloves, masks etc, and the final stage was spraying some kind of disinfective not just in the bathroom but in the immediate area outside the bathroom. So if this happens to you, please take care.
BTW, my sewer line from the house to the street does have a floodgate release valve, but it was simply overwhelmed, so I wouldn't rely soley on this device.
Richard Placone
Duveneck/St. Francis
on Sep 8, 2007 at 7:35 pm
on Sep 8, 2007 at 7:35 pm
I told my story above, no one responded, all I can say is I have a quite new home (inspected so I assume the correct valves/connections, whatever are in place) and I believe we ALMOST had this situation happen to us, the sounds were terrible and threatening, not to mention the water (thank God, it was regular toilet water that started shooting out) and NO ONE FROM THE CONTRACTOR TO THE CITY WAS THE SLIGHTEST BIT INTERESTED. I will be very, very worried the next time the street sewer needs to be cleaned out. To repeat, there was no advance notification of any activity to occur on our street and no indication that anything would potentially happen to my home, so if it does, be prepared for a big nasty surprise.
Barron Park
on Sep 8, 2007 at 8:09 pm
on Sep 8, 2007 at 8:09 pm
annonymous, the same thing happened me about 30 years ago. I installed a cleanout port in my front yard, prior to my house main sewer pipe. Every now and then it gets a 'burp', but I am protected getting it up the ...well, you know!
It is worth the investment, especially if you are replacing your main line. Hint: Do not tightly cap your port, just lay the cap on the port upside down.
Midtown
on Sep 9, 2007 at 8:24 am
on Sep 9, 2007 at 8:24 am
[Post removed by Palo Alto Online staff.]
Ventura
on Sep 9, 2007 at 12:19 pm
on Sep 9, 2007 at 12:19 pm
Our downstairs toilet had a minor explosion about a year ago. By the time we finished the clean-up and called the city to complain, the workers had left the nearby intersection -- and the city said they had no scheduled sewer maintenance for that day/location.
We've lived here for over six years. The more I learn about city and school district management, the less I like.
Palo Alto Hills
on Sep 9, 2007 at 3:46 pm
on Sep 9, 2007 at 3:46 pm
[Post removed by Palo Alto Online staff.]
Crescent Park
on Sep 9, 2007 at 8:21 pm
on Sep 9, 2007 at 8:21 pm
Wow, the Fire Department helped clean up the sewer waste. I would think that this would NOT be part of a Firefighters job.
Midtown
on Sep 9, 2007 at 9:47 pm
on Sep 9, 2007 at 9:47 pm
Editor -
Why would you remove a post that explains an engineering process?
Even if incorrect, it contributes to the discussion and violates none of your rules or any other reasonable rules I can think of for posting to a forum.
More and more, your editing is content driven, not form driven. Let forum users determine content. You can ensure the form is civil.
Midtown
on Sep 10, 2007 at 8:35 am
on Sep 10, 2007 at 8:35 am
I am disappointed that specific criticism of a failure of city government is removed, especially when the wildest slur against the president and his cabinet is allowed to ride.
another community
on Sep 10, 2007 at 2:16 pm
on Sep 10, 2007 at 2:16 pm
[Post removed by Palo Alto Online staff.]
Professorville
on Sep 10, 2007 at 2:42 pm
on Sep 10, 2007 at 2:42 pm
I've always wondered what those hash marks on PA sewer trucks were all about. Naw, couldn't be. Never mind.
Palo Verde School
on Sep 10, 2007 at 3:48 pm
on Sep 10, 2007 at 3:48 pm
This also happened to us within the last year ... came home and found water splashed all over around both toilets. I guess we were lucky to be far enough away from where the sewer "work" was taking place so that only the bowl water was splashed out of the toilet and no sewage came out. Its pretty unbelivable that standard operating proceedures in this city would produce such a potentially messy and dangerous situation.
Midtown
on Sep 10, 2007 at 9:45 pm
on Sep 10, 2007 at 9:45 pm
[Post removed by Palo Alto Online staff.]
Professorville
on Sep 11, 2007 at 12:29 am
on Sep 11, 2007 at 12:29 am
shadow-
that is exactly what seems to be happening. if i could, i would run for some high-list council job and clean everything up. i wouldnt care about the criticism i would meet. i would fix everything the city's messed up. this is absolutely ridiculous that this happens anywhere.
Midtown
on Sep 11, 2007 at 9:37 am
on Sep 11, 2007 at 9:37 am
To remove my response to Mike and leave his totally off topic comment illusrates the bias against conservative viewpoints and criticism of City hall.
Duveneck/St. Francis
on Sep 12, 2007 at 5:32 pm
on Sep 12, 2007 at 5:32 pm
My letter did not get in:
Sept. 7, 2007
To the editor:
“Exploding toilets” is not an uncommon event. (Jay Thorwaldson 9/7/07 article). On Oct. 25, 2006, I had the misfortune to have two toilets explode. I heard a loud explosion, followed by rushing water. The guest bath had sewage in the bathtub, toilet, and basin and had splattered all the way to the ceiling. The sewage had come up in the shower and toilet in the master bath, at the other end of the house, again all the way to the ceiling. My next door neighbor also had the same damage.
I, like Mr. Placone, went out to the street to find the city crew acting as if nothing had happened. They told me they were not responsible, but a call to a supervisor provided me with the authority to hire a company to come out and clean.
This required several hours of frantic calling. ServiceMaster of Redwood City were able to come in two hours, and they spent over three hours at the job. I presented my bill to the city, and they eventually paid me back.
The city must find a way to prevent these accidents!
Jane Holland
Professorville
on Sep 12, 2007 at 6:21 pm
on Sep 12, 2007 at 6:21 pm
These bathroom geysers are totally predictable events. The city crews are using Jet Rodder trucks to squirt high pressure water into the sewer pipe in the street to clear blockages. Until the blockage gives way that pressurized water will find and follow all alternate escape routes. Any competent plumber can tell you that the lateral drains running from the clogged street sewer into peoples' homes are very handy escape routes.
So we have two possibilities:
A. Our city's utilities types are too incompetent to realize this, or
B. They know it but...(I don't want to finish this sentence)
Even if they can't understand the physics they must have learned something from the several complaints they got. So I conclude option B. They know what will happen and they let it happen, spending thousands of dollars of city funds on cleanup costs each time they get caught.
Why don't they go back to the super roto-rooter system they originally used to clean these pipes? It may be less fun than their big squirt gun, but it's got to be much better for customer relations and the city budget.