That is a good point you made about the cost to repair. I am not a pond builder, just a farmer that owned a dozer and also ran one for hire as a 19 year old for another guy. But I had the NRCS design our 3 acre pond behind our house and with our dozer and scraper behind tracked tractor built it to specifications. I also built three other smaller ponds on site plus cleaned out three old ponds. So I have had at least a little experience.

But back to your comment. On a smaller pond especially, it often will cost more time and money to clean out an old pond than just to build a new one. The main reason to clean out an old pond is if it is in a strategic location where a person wants a pond "right there". I can tell from first hand experience, cleaning out and repairing an old pond is not nearly as much fun as building a new one. Then you have to do something with the muck and spoils that are too wet to work and deal with them at a later date usually.

I only had one pond leak when I was done. And I am quite sure it was roots in an old part of a dam I could not do much with because the old part of the pond still had water in it so could not do a complete clean out. It will leak down to a certain point and then hold solid at that level.

I have never purchased a liner but heard guys talk about them on Pond Boss Forum. They are not cheap to get installed either. We are in an area of clay pan soils so usually not hard to find good clay to compact to line the bottom.