Question Sunshine Tidings water

Plots consume more as they upgrade, specifically residential, argicultural and commercial consume more water as they upgrade. Check the table in the Wiki:

https://simsettlements.com/web/wiki/index.php?title=Breakdown

Just to clear up any confusion on my part, I refer to the production numbers you see in workshop mode. Built level 0 plan, after some time the number began dropping in increments of three, as if a pump was being removed. Is this an intended feature? No other settlement seems to be doing this.

As rizzla said, some plots consume water and as they upgrade, this gets higher. The workshop number takes this into account. So like a pump adds 3 water to the workshop number, a farm removes water from that number. So if (for example) a farm upgrades or a new one is built, you will see that number go down (commercial and higher level residential also use water).
Also, if you use the logistics station for the supply line, some water may be taken off to give to another settlement. This also removes it directly off the workshop number you see.
In short, when using Sim Settlements, the number you see in the workshop isn't just the addition of all of your water sources. There are also things being subtracted from it as well.
EDIT : If you go into the local plot report on the sim settlements desk, when you choose a plot type it will tell you how much water all the plots of that type are consuming. If you go into the logistics plot, you can use the terminal there to get the information report which will tell you if that settlement is exporting (or importing) any water.

Welcome to the forums reverseaquamath. One thing you need to remember is that the scores for any of the values are largely inaccurate. Plots take their own sweet time to upgrade, All this stuff runs on scripts, and there are only so many that your computer can execute before something more important in the pecking order comes along. I have found that stuff usually updates around 7 or 8 AM if there is an upgrade due and you have upgrades set to auto.

The one plot I build soon after starting a settlement is IDEK's Logistics station. If you don't have it yet... get going. This one little mod helps smooth out so many aspects of Sim Settlements it's scary. ANYTHING your settlement needs, and anything extra your settlement produces will be distributed among those settlements that also have a station. What is really usefull is that once you get a few workshops hooked up, you really don't need to worry so much about having building and crafting materials.
Above all, have a blast.