DEAR TIM: My plumbing drains occasionally clog. Do the chemical products really remove clogs from plumbing pipes? Are there safe products to use for septic systems? Do some types of pipes clog more readily than others? How can I prevent those pesky bathtub clogs? Shirley P., Marshall, MN

DEAR SHIRLEY: Welcome to the club! When I built my house 12 years ago, I was sure I would never have a clogged plumbing pipe. I used smooth plastic drain lines and sized all pipes according to code. It turns out, this wasn't good enough.

Several weeks ago, I took a bath in my kids' bathtub to soak my aching feet. Upon exiting the tub, I operated the drain lever. The water in the tub didn't budge! The drain was completely clogged. Attempts to remove the clog with a plunger and a drain cleaning snake were futile.

Hair - especially long hair - is also a major clog source for drains. Strands of hair can attach themselves to the biofilm and any rough surface or object in a drain pipe. The mechanism within bathroom sinks and bathtubs that operate the stopper are favorite collection points for hair. I believe the clog in my bathtub drain was a combination of biofilm and my teenage daughter's long hair.

Grease can also clog drains. Pouring liquid grease down a kitchen sink or any drain is a big mistake. It can solidify and choke off the drains or the main building drain line. Pour lukewarm or cool grease into paper towels or old newspapers and throw it away with your normal garbage.

The liquid drain cleaners work very well. I used a maximum strength off-the-shelf product purchased from a local grocery store. It was a thick product that poured like maple syrup. These common drain cleaners are actually a combination of regular household bleach, alkali chemicals (sodium hydroxide) and other ingredients. The bleach component works great to dissolve hair, cosmetics and soaps. The alkali ingredient works with the bleach to actually soften and dissolve the biofilm deposits. New foaming cleaners are now available that coat the entire inside of the pipes. The foam attacks biofim buildup on the side walls and top of the pipes. These surfaces are usually left untouched by the liquid drain cleaners.

To make sure I got the most punch from the product I purchased, I did something different. With a wet rag stuffed down the tub overflow tube, I used my powerful wet-dry vacuum to suction out all of the water from the drain pipe and the bathtub drain trap. This allowed me to pour the contents of the drain cleaner directly up against the clog. Within 15 minutes, my bathtub drain was flowing like new!

Regular chemical drain cleaners contain ingredients that are harmful to septic systems. The chemicals can kill off beneficial bacteria within the septic tank. If you have a septic system, you should use the enzyme drain products that prevent clogs before they happen. These products, when used on a regular basis and according to manufacturers' recommendations, will not harm your septic system. They will help to minimize biofilm buildup on the inner walls of pipes. The new foaming cleaners are also safe for septic systems.

Copper drain lines seem to have the fewest clogs. Some experts believe that the copper actually poisons the biofilm slowing its growth and buildup. Plastic drain lines are also resistant to clogs although biofilm will attach itself to the smooth insides of these pipes. Galvanized iron and cast iron pipes clog most frequently due to their rough inner surfaces. If you are installing a bathtub in a new home or remodeling project, put in a 2 inch diameter trap and 2 inch drain line. The larger pipe size will be more forgiving and easier to clean out.

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