I enjoy Water surrounded by My Heat Vents I live on a slab? I have sea in my fry vents. I live on a slab...

I have sea in my fry vents. I live on a slab house. I call the water company, after coming out they said the primary line is cracked somewhere underneath the house. That the cheapest solution may be to purely run another line from the major water source outside. After reading another similair story it get me to thinking, why did the water receive in the heat duct work. It will cost a few thousand dollars to get this repaired. However presently I am wondering if this will repair the problem because how is the water chain and heating ducts connected. Both job are pretty expensive. The water company just gives 7 days to fix this. Any suggestions. Also we are going to use a pump to try to seize the water out of the vent. How do I clean vent afterwards for mold and bacteria? Help!!!
Answers:    This is a spanking new one for me. Where in the world are heat ducts installed in the ground and later concrete slab poured on top?
The only time I own seen heating/cooling ducts run beneath the floor is when near is a crawl space or basement.
As it is possible that this is ground marine from springs or heavy rainfall and not from a broken water pipe, you involve to confirm this by observing the sea meter to see if water is running thru it.
I hope you post hindmost with some answers. You own my curiosity aroused.

EDIT:
I asked what country, state, city you are located in. I am contained by the USA.
You have to find out which pipe is leak. Does the dial on the meter move constantly? Are you sure it is a leak?
Once the pipe go under the house slab it "usually" go to the hot water oven. Depending on number of bathrooms, kitchen, washing domestic device and outside wall mounted faucets and how they are laid out can give most plumbers a clue where on earth to look for which pipe is leaking. There may be a "manifold" at the hot wet heater or any number of other places depending on layout of your house.
If you are within a warm climate next to no threat of pipes freezing then in attendance may be a cheaper option of repiping thru the attic space.
Again, this is an unusual type of construction as far as the heat system goes. That is why I am unbelievably curious as to your location.
A good plumber can isolate the leak pipe, and will need to run a bright one (or more) overhead in the attic. The hose down is in the ducts because the duct joint are not absolutely tight and hose seeped within from around them. You can probably vacuum most of it out. Depending how long they are wet will determine the possibility for mold growth. You'll smell it if it grows. Then you'll have need of to have the ducts cleaned. There are companies that do this; be sure to achieve references and call upon them, some companies are ripoffs. If I had underground ducts I would hold them sealed. There is a process call Aeroseal where they spray a sealant through the ducts and it "finds" the leak, and seals them. There is a correct chance that soil gas and critters can get into the unsealed ducts. Good luck, the fix won't be inexpensive.