Lyle comes from a clan which has long operated one of the oldest saw mills in Monab. Lyle himself helped maintain the equipment both in the mill, and the aqueducts which provided water from New River to several of the village's farms. And so, he was quite well acquainted with various milling technologies which had been in use on The Land for hundreds of years, including water wheels, cranks, gears, pistons, etc. He has said he doesn't know exactly why this existing technology inspired him (and no other millers over the centuries) to devise reciprocating piston pumps, but once inspiration had struck, he swiftly began contemplating ways to put the technology to use.
In fact, in and of itself, there was nothing truly revolutionary about the piston pump. The true innovation was in how Lyle chose to use it... and in his subsequent inventions, most notably the flush toilet. His original idea for pumps came in 888, and at first he thought they might simply be used to increase the efficiency of aqueducts. However, it wasn't long before he started thinking, if technology could be used to bring water to plants, why not to people? He began running piping from the pump he had installed in his family's mill, into the kitchen of their home, capping the pipe off with a valve and tap system, which was based on the taps commonly used on casks of beer or wine. His whole family soon became excited by the prospect of not having to go out to the well to fetch water whenever they were thirsty, and it wasn't long after that that various relatives began mentioning other uses of water that would be more convenient if it could be used without having to go out to a well or river. They hired carpenters to build new rooms for them. One was for washing clothes; another was for bathing (this room was called a water closet). In addition to the pipes used to pump water into these rooms, he added pipes which would allow the used water to drain down into the sewer.
By the end of the year, Lyle was working on developing a flush toilet, which many regard as his greatest invention (for most people seem to agree, one of the most annoying things in life had always been the need to go to an outhouse to relieve themselves). The toilet would be included in the same room as the bathtub. Over the next couple of years, he began installing his indoor plumbing system in homes and businesses throughout Monab (while another clan soon started making fixtures- sinks, tubs, etc- which were more along their line of work than of Lyle's, and much nicer than the crude fixtures he himself had first developed). At some point thereafter, Bishop Kizin incorporated plumbing into his Plan to bring organization to the world. This began in 897 with the introduction of indoor plumbing in the Northern Alliance; the engineers and plumbers there would begin introducing plumbing to the rest of the world in 901.
In 904, when the surname law was passed, Lyle's clan chose "Miller." There was, predictably, a great desire to choose this name, among many clans across the Land. However, because of Lyle's contribution to science, and indirectly to the establishment of the Second Order, he was granted the right to reserve a name (a privilege enjoyed by very few people in the world) for his family.