Our house has a sump but it's never been used. Some builders, my husband included, like to install them as emergency backup. If I was looking at a house with a sump pump I would want to know how often it kicks on at different times of the year. I would want to know if there is any evidence of water damage in the basement. Is there additional drainage (such as french drains and daylight drains). Are there gutters to take as much water as possible away from the house.

All new homes here are build with sump pits and an electrical outlet close to it. Depending on the ground water level, pumps are installed and water is PVC piped to the outside away from the foundation.
A sump pit is good to have if conditions ever change and a pump and drain needs to be installed.
In older homes it might be a retro fit because of previous flooding problems.
Since most water problems occur during inclement weather, and power outages happen during that time, a power back-up system might be necessary, especially if the basement is finished.
I'd look at the overall picture of why and where a sump pit and pump is located before making a judgement call about it's value.

We have 2 sump pumps in the basement (duplex) and 2 on stand by. Our water table is very high and we also have good drainage outside the house. When it rains etc I can hear them working as the water drains into the sewer system. We also have a back up generator.

In our area, many municipalities require a sump pump to be installed prior to the sale of a house - regardless of the age of the house or if the house has ever had a drop of water in the basement.

After experiencing a six day power outage, I highly recommend a sump pump that works off the water pressure. No electric, the sump pump never stops working during a power outage. During that outage many of our neighbors had water in their basement, we never had a drop.

We have owned 3 homes in CT. The first two did not have sump pumps in them. Where I came from before (NY metro area), sump pumps, septic, cesspools and well water were something folks had in the poorer or underdeveloped areas of Long Island when I was a kid growing up on the 50's. Actually, I never heard of sump pumps until I moved to CT in the 80's! Well, surprise, CT has them all and !!! Our first home (built in 1920) had a pebble perimiter around the basement so that if the basement did flood the water would go to the perimiter and drain. Surprise!!! We were there just a few weeks, had a hurricain, and the basement was like a pool. Called the FD and ended up renting a pump to pump the water out. For the 5 years later we never had a water problem again even the the basement was damp, but there was NO WAY we would put anything of value down there - everything from then on was up on pallets. The next home also did not have a sump pump. We again had a water issue - one time it was when the kids knocked the drain pipe for the main floor fridge out of the little hole down the basement and we didn't notice it for a while, surprise!!!! water all over the basement!! We did have a few other water issues when the spring rains came for several weeks and then started to think about the merits of a sump pump. Friends who had them never had a water issue and had finished basements and one that didn't prayed! Our current home had a sump pump and we were concerned. We ended up installing a second one at the opposite end of the basement (we have a large ranch w/ a large basement) because the original sump pump only worked in one area due to the size of the basement and that end was always damp even with our two dehumidifiers we bought. The company who initially installed the pump has a wonderful warranty and installed the second at the lowest point in that part of the basement for free!!! We also added a major whole basement dehumidifire that they sell and the basement is now dry as a bone (and has been for 6 years). Both pumps have a battery back-up and an alarm. We do have the company clean out the pumps once a year as iron builds up on the draining area of the pumps. The pumps go off quite often in the spring and it it music to my ears! That means my basement is dry and I am happy!
The upshot of this is that I would much rather buy a home that has a sump pump than not. If the owners tell me that the basement is dry and they never had a water issue, I just don't believe them! I just wish I had sump pumps in my other homes.
The initial installation of the drains and pump was very expensive, but it was just installed by the previous owners before we moved in and the company backs their work. Our last home which was 30+ year old, had septic and I always kept my fingers crossed especially since sewers were eventually coming. I never did end up dealing with well water and hope that continues!

Wow! Thanks for all the excellent replies. This is very helpful.

I don't have one where I am and have never needed one - sandy soil, on a hill - no problems. I may move though to an area that is just the opposite - flat, clay. I've been thinking I'd want to see a sump pump but my thought was that the time you might really need it is when you have thunderstorms and power goes out. What are the options for power outages and how do they work? I saw pressure no power required, battery, generator. I'd want something that worked automatically if I was out of town.

gibby3000 the water pressure based pump will work without electric. Talk to your plumber or local plumbing store about what is right for your house.

xamsx - I don't need one right now but I'm wondering about one in future house if I move. Does a water pressure pump work only in certain circumstances?

They are required here in WNY when you transfer property. I have 2, they are working quite often these days as the snow melts. I currently do not have any back-up when the power goes out, something I need to look into.

If you have well water, obviously if the electric goes, a water powered sump pump would be worthless unless your jet pump is hooked to a generator. If you're hooked to a generator, a water powered pump is redundant to run a sump.

gibby300: Does a water pressure pump work only in certain circumstances?

Nope. It works just as a regular sump pump, except you don't have to worry about the electric going out as electric is not necessary for it to run.

weed

what part of the country do you live? any idea of the soil type - clay, loam, sandy? Is the house on the downward slop of a hill? any idea on the water table in the area?

I live in the mid-atlantic region and sumps are standard here for new homes and have been for quite some time. They are typically part of a foundation drainage system designed to relieve hydrostatic pressure that can build up on the perimeter of the foundation walls. So if this happens to be your case then having a sump pump is a good idea. My pump runs a one or 2 times per day for brief periods - especially after hard rain or snow melt.

I do know of one case in my area where a person built a home and they put the foundation too low - and the lot is on top of an area where the water table is high. In this case - the pump runs almost continuously (except in dry season) and pushes out a lot of water (like 3 gallons PER MINUTE!). If the pump ever failed, the basement would flood in less than a day. If that is the case - then I would be very concerned.

So the answer to your question is that it depends on a number of factors.

I can see this is something I really need to get a handle on if I do move. I'm accustomed to living where I have a well and septic and likely would have that in the future as well - along with a sump pump - and a generator??????? I did look at one house that had a generator - I think I'm beginning to understand why.

I live in St. Louis, and much of the soil is dense clay. Buying a home with a sump pump makes more and more sense.

Gibby, a generator can be a great thing, not just for running a sump pump. In the past 3 years, my power has been out for up to a week due to summer thunderstorms and also winter ice storms that pulled power lines down. Luckily I was able to stay at my dad's, who did not lose power. (I brought the contents of my fridge, freezer, and my two dogs!) I am seriously considering buying a portable generator for those times, because I anticipate it's going to happen again.

A whole house generator will run an electric sump pump. A portable generator would be tough because the portable should not be in the house. You'd need the sump pump near an outside door to run an electric cord to run the sump pump, so as weed30 said, a portable generator to run a sump pump is not feasible.