There are lots of ways to save water in your home with just a few tips that pay off relatively quickly! Note: In your search of appliances, you may see Tier 1 - 3 ratings, and while these ratings don't refer to the DoE Energy Star ratings, they refer to CEE or the Consortium for Energy Efficiency, and are certainly worthy of looking into. Tier 3 is the most efficient going well beyond what energy star asks for. I would go into more detail but the requirements change per appliance.
Tip #1: Install water efficient shower heads.
If you have a shower head that dates back to 1992 or earlier, your shower head could be using up to 5.5 gpm (that's gallons per minute)! Newer models are federally mandated to not exceed more than 2.5 gpm but personally, you can find some great looking shower heads out there that use a lot less! My personal favorite is by Niagara Earth Massage 1.5 GPM handheld shower head. I've been using it for about 2 years now and it's great. We live in an area with very hard water (Texas is practically world known for how hard it's water is...) and at the head it says perfectly clean and the chrome is very pretty. Occasionally for cleaning we'll wipe it down with some vinegar to remove all of the calcium and it looks good as new again. And the great thing about it is that it uses only 1.5 GPM instead of 2.5 or more!
Cost Savings: If you have 4 people in your home with two showers and you replace both of them with this model or another 1.5 gpm model, and each person showers for 10 minutes (assuming you had a 2.5gpm model previously and your water/sewer costs is $0.0095/gal) you'll save 29,200 gallons per year which equates to $277.40 per year with only an initial cost of $38.00 (taxes and shipping included) which means it'll pay for itself in 50 days! Not too bad!!
Tip #2: Install 0.5 GPM Low Flow Faucet Aerator
Now that your shower is using only 1.5 gpm from that clunky 2.5, lets reduce the water used while using the sink. Currently, faucet aerators are allowed to pump out 2.2 GPM! Can you image using roughly the same amount of water that you shower with just to wash your hands?!? I think that is way too much, so lets bring it down to 0.5 GPM. Currently I've installed 0.5 GPM low flow faucet aerators in all of my faucets with the exception of the kitchen where I want it to flow faster to fill up those big pots and among other things.
Cost Savings: Again, lets assume you have just 2 sinks (both 2.2 GPM aerators replaced with this 0.5 GPM aerator) with 4 people in the family and each day they use the sink for about 10 minutes between washing their hands several times a day, brushing their teeth, cleaning, etc. Replacing it would save you about 49,640 gallons which is $471.58 per year and it'll pay for itself in under a week!
Tip #3: Fix leaky faucets, toilets, etc!
A leaky faucet that is dripping one drop per second results in $1.00 per month increase in your water bill. If you're handy you could probably repair that leak with that one dollar with things you have around the house.
Likewise, if you notice ripples in your toilet that it's leaking more than just one drop per second and should get fixed immediately. An easy way to determine if your toilet is leaking is to put some food coloring dye into the basin and check to see if your water is that color 30 minutes later. If it is, then it's leaking, otherwise you're safe.
Lastly, if your hot water heater is leaking, then it's time to replace it. If you live in a place that doesn't have hard water, I would recommend getting an energy star tankless hot water on demand system. You'll have hot water faster, no waste from keeping water hot when it's not needed and a smaller footprint. Likewise, if you live in a hot climate like texas or arizona, then I'd suggest thinking about installing a solar hot water tank. Let the sun do the work for you. :-)
But no matter what you install, make sure it's energy star because it'll pay off over the lifetime of the unit and make sure you follow its maintenance schedule so it will live a longer and more efficient life. Also keep in mind that you can lower the heating on a hot water heater. There is no need to keep it at a temperature that will scold you.
Tip #4: Appliances: Dishwasher
If you want the best water and energy conservation you'll need to go past just faucets and shower heads and actually get more energy star appliances. If you get an energy star dishwasher, you'll end up saving even more especially if it has a booster heater (which usually pays for itself within a year). With a booster heater you can raise the temperature of the water up to 140F, which is recommended for cleaning dishes. Although many people think they can wash dishes more efficiently than a dishwater, that's rarely the case as long as you have a dishwasher that's from 2000 or newer. A full dishwasher can wash dishes a tremendous amount more efficiently than a person. Another benefit of energy star models is the availability of different cycles, use shorter cycles to save even more water.
Tip #5: Appliances: Washing Machine
Washing machines by their very nature, consume a lot of water. However, by purchasing an energy star, you'll have the option of saving more water than others, a tremendous variety of different options on what to run your load at and maybe even a chime when it's done, like ours. :-) Smaller capacity washing machines typically have better efficiency ratings than larger ones. More efficient models will also make the dryer run more efficiently as well because they'll spin the cloths better and make them drier to begin with. If you're wondering what the different between front loaders and top loaders, front loaders typically run using less water than top loaders consequently, using less energy.
The best way to run a washing machine, in my opinion, is to run it with full loads and if you're only rinsing the laundry, run it with cold water, no need to do warm or hot.