What area does my sump pump drain?

The thread about sump pumps reminded me.
I live in a row of 8 townhouses. I'm at one end. Every house has a sump pump, in part because Baltimore County law requires them now for basements below grade.
I'm sure that sometimes water comes out of the pump in the house next to mine, but how much, and only from the front of the house or the back too??
How would rain falling behind the house get to the sump pump for people who live NOT at the ends of the building but in the middle. Would they really run the 4" pipe all the way from the back of the house to the sump at the front underneath the foundation and the basement floor the whole way?
Thanks.
Details if necessary: My pump is at the front right corner of my house, and the right side of my house is the end of the building. I have two 4" corrugated perforated inputs, one pointing forwards and to the left, the other pointing to the right and backwards.
I guess the first one goes in front of my house, where most of the land is covered by the front stoop and a paved are for barbecue grills, lawnmowers and garbage cans. It sticks out about 6 feet. All of the houses have that, so any rain that gets in that way has to be from the 18" section with no stoop and no pavement where there is grass and the input for the oil tank is. I guess my pipe only goes the width of my house.
The second pipe which I think goes along the side and back of my house gets much more water, not surprisingly, but does it only run the width of my house, or does it run behind the three other houses on my half of the building with 8 houses.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It is impossible to know without excavating. Building plans usually don't detail such things but you could check the building department of your town to see if they enforce any standards.
Ideally each house has their own separate drainage system. Yes, the pipes are often installed under the foundation and floor to get to the sump, and to provide floor drains for the basement, so it is possible they did that, but who knows.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.