If you are just using the water for irrigation, why worry about cloudiness?
If you have deep, sandy soil, it may be hard or impossible to seal a well from surface water. In my area, the well drillers install a 20 foot steel well casing in a new well, and then dump in as much bentonite around the casing as will fit. I don"t know if there is a law requiring them to do that or not. However it seems to work fine on the wells I have been around.
The well where I grew up had been punched with a cable drilling machine in about 1910. There had been a windmill, but when we moved there in the 1950"s, the well had a jet pump with a pump house built over it. We later changed over to a submersible pump. I don"t know how far the casing in that well went down, but every Spring we had problems with surface water contamination for about a month. The water would get very brown, like apple cider vinegar. It only really bothered when my Mom wanted to wash white clothes. My Dad had the brownish water tested, and the water was said to be safe to drink, so we did. After about a month or so, it would go back to being crystal clear.
We tried several things to help keep the water clear. I hand dug a ditch across a field to eliminate a puddle that would develop that was not too far from the pump house, but that did not seem to make much difference in the color of the water, usually about March.
My guess is that there were many fractures through the rock around our farmstead, and when the Spring thaw occurred, there was so much available surface water that it made its way to our aquifer. Our well was supposed to have been about 200 feet deep with way more water available than we ever had pump to test its capability. It was a good well, but it had the fairly small problem of the water getting brown for a while every Spring. We just accepted it. Good luck!