Yeah,  Ive known about this for decades. Those transformer substations are a big problem but the entire country would be in pandamonium immediately. 

People need  a water plan. Hot water heater you are good for about four people per day per gallon. Save good liquid containers and stash water where a leak wont hurt anything.  

A five pound can pork & beans about 5,000 calories for five dollars.  They range from about 120 -  180 per serving.  Cheaper stuff has more fat I think. One thousand per day is survival easy. 

Water purification tabs are cheap as are water straws used by hikers.  Buy low power led flash lights.  The cheapest Everready at home depot runs for several days straight with the single heavy duty D cell that comes with it.  I got a two pack for about $5 then some alkalines last three or four times longer. A few hundred dollars and you could shelter in place for a long time