I love my Blue Swedish too!
I am only mentioning this because water in the duck house is a hot topic that I have seen go back and forth a couple times and I think we have to keep in mind that there is membership here from all around the world (and those speaking The Queen's English undoubtedly think I should have said "there are membership"

). And If I limit this to two places I have actually been, advice from Marquette, MI may not apply to Phoenix, AZ and vice-versa.
I think the water thing depends a lot on where you live too. Ducks use water the same way we do with the notable difference that they don't salivate. So they need water for washing down food and they need water to rehydrate especially when they are losing water to heat due to panting. So no question about it, ducks NEED water if they have food! But if you live in a place with warmer nights especially if you live farther south where you have longer warmer nights, your ducks are more likely to need water during the night to offset dehydration. I know when I lived in NY, even though that is a fairly cold northern state, the summer nights were often warm enough that it was uncomfortable without AC. In Montana, even on days that reach 100F in the day, at night we can turn off the AC and air out the house comfortably during the hours that the ducks would be in their house. Plus living farther north, they are only in their house in mid-summer about 6-7 hours. I watch my ducks when they come out of their house in the morning. They don't bolt for the water. Some go get water first. Some eat some food then get water. Some just lay down outside for a while then get food and water a little later. That is kind of like my mornings. Most of the time when I get up, I have a little something to eat and drink within the first half-hour, but not always and sometimes I might not get anything until mid-day. Part of this is learned behavior too. When I first was putting my ducks in their house, I experimented with putting water in and they would always end up emptying their waterer into the bedding and not having water anyway. (BTW - your method seems very good for someone who wants to use water in their duck house - much better than anything I tried.) The first night I put them in with no water, they came out the next morning bolting for the water and I was afraid no water might not work. The second night, shortly before it was time to go in, they filled their crops with food and drank water for about 10 minutes (in shifts) before they went in. The next morning they came out happy and non-rushed. So I think that some ducks the first night went into the house a little thirsty thinking they could drink whenever they wanted and by morning they were parched. But after one night they learned make sure your get some food and water before you go in. (Smart duckies). Since then, I make sure they get out every morning but at least once / week (either live or off the cameras), I watch them as they come out of their house. If they ever act like they really NEED water, I will probably set up something like you have. We all have to try to keep our ducks as safe and healthy as possible and there are some things that depend on multiple circumstances such as mold/fungi in the area and humidity / ventilation. I do really like the idea of waterers in the house though as long as they have another source through the day to wash their eyes and nares, that sounds like the cleanest plan that would include water.
My oldest ducks (Tella & Ettie) will be 3 years old in August. All my ducks except my WH are on winter break so I am only getting the one egg at the moment. Hopefully Tella and Ettie will not decide to retire this year

but that means I can't tell you much on either account, I haven't had a duck go from old age and this is my second winter with laying ducks - last winter, my ducks dropped production down to about 50% overall. This winter they stopped for 2-1/2 months and all but 1 are still stopped (my WH has laid the last 2 days.) @Amiga
has 11 runners that are around 6-8 years old I think... How are the eggs Amiga???