A friend asked me recently about Social Security coverage for her part-time housekeeper. This subject is not discussed very often, and there may be quite a few of you who should be familiar with the rules.

If you have a maid or housekeeper, gardener or handyman, or even a babysitter whom you employ on a fairly regular basis, you may be liable for providing Social Security coverage for him or her.

The test is the amount of wages you pay, and the floor is $50. If you pay that amount or more in any calendar quarter, you must deduct Social Security tax from the employe's pay and report both tax and wages quarterly to the Internal Revenue Service.

(Tax is not required to be withheld for anyone who is operating as an independent contractor rather than an employe. There is a fine line between the two, involving the amount of control you exercise over working conditions. If your worker claims to be a contractor who is reporting independently, you can accept that definition.)

If your household worker meets the earnings test, make a record someplace of his name, address and Social Security number (SSN). If he doesn't have one, direct him to apply for a number at the nearest Social Security office.

Keep a record of wages paid, and deduct 6.7 percent of the wages -- an amount you will have to match with your own contribution. Within a month after the end of each calendar quarter submit Form 942 to the IRS showing the employe's name and SSN, the wages paid during the quarter and the Social Security tax withheld.

Along with the report send payment for twice the amount withheld -- 6.7 percent of wages contributed by the worker plus another 6.7 percent paid by you.

Pick up a copy of SSA Publication 05-10021 at any Social Security office. (If you call, they'll mail you one.) It contains all the instructions plus a post card for requesting the necessary reporting forms.

This may seem like a lot of extra work; and your employe may not be very happy over the idea of losing a small chunk of his or her wages. But we're really talking about perhaps 30 minutes of your time every three months.

And it will provide not only Social Security retirement income but, perhaps more important, monthly payments to the worker and the worker's dependents if he or she becomes disabled and can't work.

While we're on the subject of Social Security, I've answered letters on a couple of occasions about the need to obtain a Social Security number for a child when opening a savings account or mutual account.

I did respond to the specific question asked in each case -- but it might have been more helpful if at the same time I had explained how to apply for the child's number.

You can apply for a Social Security number for your minor child either in person or by mail. Application is made on Form SS-5, which may be signed either by the child (if old enough) or by the parent, other relative or guardian.

With the application, bring or send the public birth certificate or religious birth or baptismal certificate, together with some evidence of identification. For a child this could be an insurance policy, school ID card, hospital or vaccination record, day care or nursery school record -- almost anything that will confirm the information on the birth certificate.

The Social Security Administration cannot accept photocopies that you have made, even if notarized. You must bring or send either the original or a certified copy obtained from the original source. These records will not be kept -- they need only to be seen; if you mail the request, the documents will be returned to you.

The issuance of a Social Security number to a small child may seem like Big Brother government. Actually, it's a very handy peg to hang your identification on, used for things other than work records -- like driver's license, military ID, etc.

The number may seem impersonal, but think of it simply as an extension of the child's name. If your children don't have Social Security numbers, I recommend you apply for them.