A screen shot would be very helpful.
One common mistake that leads to lot of confusion could be:
You have two (or more) separate road maps in your city which are not connected to each other. That leads to two separate sewage systems as well. While one sewage system is adequately supplied, the other system is undersupplied.
So you have to take care, that all your roads are reachable from any other road in your city.
Hope this helps, good luck.
Simcitybuildit
How to make a screenshot depends on what device you are using.
On my android tablet it is:
Press and hold the 'Power' and 'Volume down' buttons at the same time for a few seconds.
You have to google the procedure for your device.
When you reply to a message, there is a button to attach files. Tab on it. On my device I have to choose 'Documents' to show the latest files I have used. Tab on the Screenshot file, that's it.
Your sewage capacity is 62 but your demand is 63. You have to build at least one more Small Sewage Outflow Pipe.
