Dear Jim: Our water bills are pretty high. We still have two old water-guzzling toilets which we like and they flush well. What can we do to them to save water instead of purchasing new, efficient toilets? – Claudia H.

Dear Claudia: Toilets are one of the major water consumers in most homes and they do contribute significantly to your high water bills. Installing new 1.6 gpf (gallon per flush) toilets is your most efficient option, but you can make some low-cost improvements to your old toilets.

It helps to understand how a toilet works. The majority of the water from the tank flows down inside the toilet base to create a suction, which draws the wastes from the toilet bowl. Only a small amount goes into the bowl to clean the sides and fill the bottom.

Add-on dual-flush kits are very effective. These provide two different water volumes per flush. It requires less water to clear the bowl for liquid wastes than for solid wastes. You push the flush handle down for a low-volume flush or up for higher volume. The kits are inexpensive and can be installed in a few minutes. They work by varying how high the flapper valve at the tank bottom is lifted. If it is lifted just a little, it flops back down and stops the water flow before the tank is totally emptied. For more water, the flapper is lifted higher.

A rapid-closing flapper valve is another simple-to-install device. Remove the old flapper and slide the new one over the overflow tube in the tank. These flappers are designed such that the air inside one, which holds it opened when the toilet is flushed, comes out quicker so it closes sooner. Adjustable rapid-closing flappers are installed the same way, but they provide the option to vary the water volume per flush.

Each toilet design is unique and some may require more water volume than others. One flapper design has various size holes in the end. A rotating cap over the holes allows only one hole to be uncovered at a time. Selecting a larger hole lets the flapper close quicker. If this does not provide an adequate flush, rotate the cap to select a smaller hole.

Another adjustable flapper design uses a float on the chain from the flapper to the flush handle. By raising or lowering the float, you can control at what tank water level the flapper closes and stops the flush. The old standby is the toilet dam, bag or a brick in the tank. These effectively reduce the water volume of the tank.

There are many designs, but the plastic bag kits are the easiest to use and are adjustable. Adding an adjustable diverter can direct more water to the tank so it fills faster. The following companies offer water-saving toilet improvements: American Water & Energy,

(800) 950-9058, www.americanwater.com; Athena Controllable Flush Co., (888) 426-7383, www.athenacfc.com; Lavelle Industries, (800) 528-3553, www.korky.com; Niagara Conservation, (800) 831-8383, www.niagaraconservation.com; and Rectorseal, (800) 231-3345, www.rectorseal.com.

Send inquiries to James Dulley, Bangor Daily News, 6906 Royalgreen Dr., Cincinnati, Ohio, 45244 or visit www.dulley.com.