Descale municipal water supply line
Are you sure its a scale build-up. Just a few things to note. 

Here is just a shortlist of things to try first:


Make sure that your water meter is not the cause. there is a filter
in most meters, and it is prone to build up with gravel and small
stones, The filter is on the meter on the inlet pipe side, but you
may need the munic to do it for you.
One possibility is that the towns pressure has decreased due to more consumption, that may be the cause of your pressure loss.
Obviously look at all the gause filters on taps and check they are clean (i am sure this has been tried already) 
Generally, Scale and sediment are more prone to build up on joints and T's, rather than the straight sections, one method is to try to locate the joints and have someone replace just those for you. 
See if you can locate your curb stop (shut off valve) and increase flow slightly


Scale build-up will occur where there is a rapid change in pressure or temparature (water heaters specifically), however, in your case any reduction valves or joints would be the first place to look. 

There are actually many types of scale, and the removal technique should be suited to the type of scale,  A Poor choice of removal method may actually promote rapid recurrence of scale. Scale Strength (Delicate, brittle, whiskers, crystal, rock like) , texture and purity (one mineral or multi-mineral) are all determining factors


Carbonate minerals are highly soluble in Hydrochloric acid 
Hard Sulfate Scale more difficult since it has a low acid solubility
(need    chelating agents)


The common way to clean scale of the pipes is an acid wash, sulfuric or hydrochloric acid is normally used, whereby the pipe is opened up just after the meter, and connected to a pump, then one tap is opened at the end of the line, and a bucket is placed, then the pump circulates acid through the pipe and flushes the system. The problem with this process is that the acid does etch the pipe and create craters for accelerated scale build-up in the future.  The system must be flushed extremely well, since the spent acid solutions of scale are excellent incubators of fresh scale.