I have two sump pumps in my basement. In case of a power outage I

I would check into getting a propane generator as it does not take electricity to run.

Ugh hit button with finishing. What we did was have an extra propane tank put in and bought a propane generator that switches on when the electric goes out automatically.

We also had a generator that ran our furnace and sump pump when electric went out. Our sump in the house we had in the mid eighties ran all the time. Neighborhood was built on a swamp. The one time the sump wore out, I spent an hour emptying the hole into the washing machine while hubby ran to get a new one. When it filled I would run the spin cycle, then fill it again..

How about a plain ole hand pump, visit a marine supply store (as in bilge pump).

I once was hired to do some repairs in a basement with flooding problems, and hit had 2 sump pumps going. 1 pump to control some spring water/ hillside run-off,(subsurface water from an adjacent farmers field), which could have been eliminated with a properly installed french drain to divert the water from ever entering the basement. The other sump pump was cycling every 7 seconds because of the constant flow coming through a 4" tile at the base of the foundation wall and into the sump well. The former husband of the woman I was hired by had cleverly plumbed the sump discharge into the sewer drain in the next room, running to an abandoned septic tank, on a hunch as to WHY, was this pump cycling so frequently, I poured a cup of chalk-line chalk into the sump well which turned the water Red, (same color as my chalk), within 20 seconds the water coming in through the 4" tile became red!! After showing the woman what I had discovered (using the red chalk again), she said that a year or 2 prior they had to replace their septic system with a costly new system because the old septic had a plugged up drain-field. with her permission I made a temporary drain line from the pump discharge out of the basement and about 40' away from the house onto a down hill slope away from the house. Within 20 minutes of pumping out through the temporary discharge pipe, the sump pumps cycling had slowed to once every 2 1/2 minutes (from once every 7 seconds!!!), and by the time I was getting ready to leave for the day,(about 1 1/2 hrs later), the pump was only cycling every 12 minutes. Her electric bill dropped significantly !! In her case, she could have controlled the water flow into her basement with a Gravity drain system, but she didn't have the funds to pay at that time. As I told her, there have been MANY Sump pumps installed out of laziness and the fear of using a shovel to install a gravity system. A sump pump is only effective when it runs and is always just One more thing to break down or have to maintain! As far as your fear of an EMP, yes it is possible, but given the REAL catostrophic aftermath of such an event, is your basement going to be your biggest concern? Maybe you could sell buckets of water to your neighbors so they could flush their toilets!-- At least until the the municipal sewer system fills to the point it will no longer be able to "PUMP" the water to the treatment plant! I would consider the GRAVITY of the situation!