I sat across a desk from a pony stroking their beard. "Hmm," he mused softly. "A curious request."

"A simple thing." Underplaying the importance and magnitude of its effects seemed prudent. "The focus is on longevity and ruggedness. All it has to do it clean any water passing through a pipe. I want nothing but pure water coming through. Not even the tiniest specks of anything else should get past." I wasn't quite ready to break his mind with germ theory.

"And what would be done with what it catches?" he asked with a raised brow. "Destroy it?"

"What are the options, and their costs?"

"Lay it all out," spoke Easy, reminding me that she was there. "So we can make a pick."

"Well, destroying all that is not-water will cost the most to start, but be least likely to have long term issues." He tapped his hooves together lightly. "The most expensive part of this process will be procuring Pure Water." He said it with capital letters, you could tell. "That never comes cheaply, but is required for the creation of magic that creates entirely pristine water, either wholecloth or rendering existing water. You're looking for the latter, if I understand correctly?"

"Right." But... "If Pure Water is literally pure water, I think I can arrange that."

His brows went up together. "Can you?" His horn glowed, setting an ornate jug down in front of us. "I will require this to be filled then. It should be clear enough to be entirely transparent and taste of nothing but water. It will be the example the magic will cleave to and strive for."

"This may be a silly question..." I reached for the jug, drawing it closer. "But why not take already pure water from an existing water production point? That would be free and easily available."

He smiled softly. "You would think that. I can't even hold offense to the thought. Every mage thinks that until corrected. Water created wholecloth by magic is subtly different than true Pure Water. Using created water as Pure Water creates an unfavorable taste and texture, and we do not suggest it. This is why it is costly, for it must be done right."

Except I knew how to filter water, especially manually and for one specific purpose rather than building a filter that would last years on my own. "I'll provide that, without magic."

"I look forward to what you can do," he said with some doubt in his voice. "Putting that aside, if you can do that, you've removed much of the cost. The enchantment in this case is rudimentary. We can place it on a ring to be fit snugly around the pipe to be cleaned. Will you be providing a ring of the correct size?"

I felt like we were making progress. "I can work that out. Besides fitting on the pipe tightly, how large should it be?"

He held up two hooves about an inch apart. "This wide. A little longer will give us more room, but no smaller. If you're providing the ring, we can't start until you bring it to me." His ears suddenly perked. "Ah, do use the purest metals."

"Define pure?"

Easy thrust up a hoof. "He means it should be free of rust, dirt, and other things like that. It should be nice and shiny, inside and out."

The mage nodded. "As she said. Cut-rate smiths may produce metals lacking in that, and magic does not hold as well to such metal. If you want it to last, make sure to use only the finest materials."

Stainless steel would be nice... but extremely beyond Equestria's current industrial base. "I'll find a quality smith and return with the ring, and the Pure Water." I hefted the jug. "So if I'm providing both of those, what will the cost be?"

"Then all that would remain for us to do is place the final spell on the ring. Are you certain you would not want water created? It's much more reliable." He furrowed his brows a little. "We can fill a tub in moments without issue."

I wanted to fill all the tubs in the entire city... "That reminds me. Assuming this was placed around a pipe, would there be a limit in how much water can pass through it or how quickly it flowed to be effectively cleaned."

He snorted at that. "Provided you don't damage the pipe, our magic will operate on all water that passes through it. Be mindful living things don't pass through... it would end poorly for them."

That was good, but also meant we should avoid allowing fish to slam into the deadly magical trap, though... "I'll bear that in mind, thank you."

"So what's the cost?" asked Easy with no subtlety.

I held up a hand at that. "This will not be the only project I have, just the first."

That seemed to relax him. I figured he was hoping I would be an opportunity for funds, just as Mason had. "That will vary partially based on the size of the ring. But to give an estimate..." A paper slid forward with numbers spread across it, showing different sizes to different costs.

What intrigued me right away was that the larger rings cost less to enchant. "Query, if the ring was broken, so it could be easily attached to the pipe and clasped into place, would that affect things?"

The mage shrugged softly. "Bring it to us already clasped. It will not function until it is clasped again. If that is all, I should resume my duties. It was a pleasure." He nodded lightly but made no motion to move.

It was our turn to get out. We said our goodbyes and departed, a jug in my hands. Easy hopped ahead lightly in a sprightly trot. "Well that went well. Those numbers don't even look too scary. I mean, I wouldn't want to pay it, but for what you're doing, not bad."

I needed a better feel for Equestrian economy and how far the bit went. From what I had experienced so far, the rings weren't cripplingly expensive. About 3 of the dinners we had enjoyed for all the ponies present to get something that would last for quite some time and service so many other ponies?

"I can see why a common pony couldn't afford anything like it."

Easy nudged into me. "There was a reason he tried to talk you up into making water. Bet it's more expensive."

"And slower." A tub in moments really was nothing for an entire city's demands. "Next step:"

"--Wait for Soft?"

An option, but... "I'd rather have a look at the water source. No matter how Soft's efforts go, we need to know the lay of the land." I hiked a thumb towards the exit. "Ready for a hike?"

She stuck out her tongue, but veered towards the exit through the halls. "Yes, Sir. Pity I never learned how to teleport."

I walked alongside her, watching the guards standing at their stations and the nobility that filtered through the halls with us. "How hard is that kind of magic?" Twilight could do it, in the future, and Starlight, but that was only two confirmed unicorns out of untold others.

"Simple, in theory." She twitched an ear. "In practice, complicated. The penalties for messing up are pretty high too. I'd rather walk for a good few tens of years than teleport wrong for a day, you know?"

We emerged from the castle into the light of day. A guard cleared his throat. "Sir, should I call a carriage?"

When did I get carriage access? "If one can take us to the edge of town, closest to the water source?"

"Of course, Sir." He dipped his head and left. There was another guard there, the post not unattended.

Easy laughed triumphantly. "Or we can ride in style, that works too. They must be starting to like you in there, Boss."

"Us. They like us."

Her smile only grew. "Yeah. Let's go check out that water."

A carriage eventually came up to the steps and we went down to meet it. The interior was simple and soft and we were born along bouncily through the streets. The best part was perhaps that fragrances in the wagon kept most of the foul odors in the city at bay.

We were soon there, announced with a rapping on the roof. We disembarked and the unicorn driver nodded towards us before he pulled on the leads. He did not lead horses, they were ponies with the leads attached to their sides, not their mouths. They followed the directions though and soon started back into the city.

Ponies helping pull other ponies along? It was... different. It worked for them, and if the ponies were paid well, what harm was there? "Alright, where is the water source?"

Easy pointed as she walked. "This way, down the hill."

I looked up at the purplish stone that made up the mountain rising higher still away from Canterlot, then followed Easy along. It wasn't that far, maybe a ten minute hike through the countryside before we started hearing the gurgling of water. There it was, a pool of water that ran off into a river going down the mountain. "Perfect, almost... Where does this water come from?"

"Come from?" Easy squinted a little. "What do you even mean by that?"

"Water does not just... happen, magic excepted. This water is going that way." He thrust a finger in the direction of the river. "But it had to come from somewhere. I'd like to know where that is."

She looked left and right. "I don't see any rivers leading to here, so don't know, boss."

Well, logic time. Water. It moved sideways to diffuse, and it moved down to follow gravity. It went upwards only when it was vapor. This wasn't a raincloud, so up was not a direction it was moving. My eyes turned to the mountain that rose above Canterlot. "This isn't the source."

"Is isn't? Sure looks like a source..."

"Do you have a water breathing spell?"

Easy blinked rapidly. "Huh? Sure." She lowered her head at me and with a bright fit of sparkles, a bubble was made around my head. "Ta da! I used to love that spell for hiding underwater and playing pranks during the summer. Poor little colts never knew what hit them."

I smiled at the image of a young Easy impishly pranking people with her magic. "Can you do yourself at the same time, and how long does it last?"

"Sure." Her horn glowed as a new bubble appeared, her voice sounding a little distant going through it, "It'll last as long as I power it. It's not that stressful as spells go. What are we doing with it?"

I pointed into the pond. "We're going for a swim. Do you know how to swim?"

Her eyes half-closed. "Didn't I just tell you what I used this spell for? Of course I know how to swim." She divested herself of her clothing without delay, folding them neatly in her magic. "You going to get naked? I know you're all touchy about that, but, really, I've seen you going to town on Water... you have literally no mysteries left for me."

My cheeks began to burn without my input on the matter. "Mostly..." I was soon down to boxers. I set the rest aside carefully. Plunging my phone into the depths certainly felt like a bad idea.

She snorted softly. "Those hide nothing." She rolled her eyes towards the water. "Are we looking for something, or just enjoying a little swim? I'm not opposed to either. It's been a while since I had a good swim."

"I have a feeling we'll get that..." That was, possibly, an ill-advised idea... "We're going to swim against the current. Wherever the current is going, we'll go the opposite way until we can't anymore."

Author's Notes:

Good idea, bad idea, or terrible idea? You decide!

The filter won't be onerous to obtain, hirrah! With it being on a clasp, the pipe can be replaced if needed without busting the filter in the process.