I'd consider that comparable to a utility pumping sewage.
I do not understand the desire to compare problematic internet service to sewage-pumping through the potable water supply. Are you desperate for superlatives which will make the internet service providers look bad?
I work partly from home and, while not quite "utility pumping sewage" level of crisis, a badly-timed internet blackout at my apartment can be a serious problem for the whole team.
In contrast, I've had several 30 minute to 2 hour power outages, and lots of power outages lasting less than a minute.
On the other hand, a short internet outage would not necessarily be noticed, because there's not a big change in ambient noise when the internet fails, nor do i have to reset the time on my appliances.
Now, my Internet being slow...that's not uncommon at all. I've also had them randomly charge me an extra $50 "by mistake", as well directly and repeatedly lying to me about what services/packages are available.
I'm in central Austin, and so ready for Google Fiber. My parents live out in the middle of nowhere, and Internet outages are quite common for them, easily exceeding power outages.
It's clear that Parent is saying "Comcast delivers shitty service" -> "water utility delivers shitty water".
It's a (possibly unintentional) pun, and I'm quite certain that Parent was able to get their point across regardless of technical inconsistencies.
But don't let that stop you in your quest to nitpick on the internet.
I'm not nitpicking, I just think the comparison doesn't make any sense unless one is trying to make Comcast out to be some sort of villain spewing sewage through everyone's taps. An internet outage is rightfully characterized as similar to a power outage or drought. The latter two are caused by poor planning and capital investments by power utilities, and the former is caused by similar behavior by the ISP. Both are fairly common.
Shouldn't you be looking at water restrictions which the utilities blame on drought? This is the most similar type of event to the Comcast outage which you are describing. Both could have been prevented through better planning, capital expenditures, and forethought. If this is the comparison, both Comcast and many water providers fail, though the internet providers have gradually improving products, while the utilities do not (as far as I know). Most industries' products do not fall from the sky, yet they still manage to provide an adequate supply.