Oh, those leaky faucets: the hidden costs of home ownership

You've signed on the dotted line, the house is yours, and you move in. Suddenly, the plumbing springs a leak, the evergreens fail, and property taxes go up.

While most people prefer to buy a house instead of renting, surveys show, home ownership still is an expensive proposition. Of course, there are tax advantages as well as all those intangible benefits of owning your own place, but home ownership still involves more cost than the monthly mortgage check.

Discovering what a house costs in terms of upkeep, utilities, insurance, taxes, occasional redecoration inside, and outside landscaping may be more than most house buyers want to know.

Yet without that knowledge, homeowners risk a hit-or-miss budgeting jolt that could catch them with their bank balance down.

Here are some of the items to add up: * Maintenance.

Perhaps the least expected and most expensive ''extra'' cost is upkeep.

Be it a costly plumbing job or simply a new faucet on the bathroom sink, the cost of maintaining a house can take a big bite out of the monthly budget. It is estimated that the average homeowner spends an average of $27 a month for home repair and upkeep, but in some cases it is far more. Someone who is handy with tools can cut the cost considerably by doing much of the work himself.

Big-ticket items, such as new siding and a new roof, must be taken into consideration, along with the lesser costs of new storm windows, fencing, weatherstrip-ping, gutters, downspouts, and the like.

Tools are an infrequent purchase for most homeowners, but many people are stunned by what they spend over the long pull. The first-time home buyer is likely to be surprised by the number of tools required to maintain a home.

Some maintenance costs seem insignificant when viewed separately, but they all add up. Furnace filters, switch plates, caulking, and grass seed and fertilizer are small-ticket items by themselves, but over a five-year time span they run into many hundreds of dollars.

The cost of upkeep is, in part, determined by the size and location of a house. Naturally, a small home requires less paint than a larger one. But if the smaller house is situated near a factory, it will require more frequent painting than a house some distance away.

Cost also depends on the age of a house. An older house may require new plumbing or wiring or a new roof, while a newer one may not require that kind of work for another 15 or 20 years.

On the other hand, an older house may be surrounded by well-established trees and a desirable lawn. New homes are often built in undeveloped areas that call for extensive landscaping, and this can result in a lot of money.

Of course, when you sell the house you may recover a substantial part of the upkeep investment. Be warned, however, that a large investment, such as new siding, often does not pay for itself when a house is sold.

If you have a $50,000 house in a $50,000 neighborhood, putting $5,000 to $8, 000 in new siding will not increase the value by the same amount. If you do improve your home beyond the value of comparable property in the neighborhood, you'd better figure on living in the house a few more years so as to get your money back.

Other expenditures, however, such as roofing and new fencing, are more likely to increase the value of the property.

In general, keeping a house in overall top condition is more likely to make it appealing to a prospective buyer and thus bring a better price. * Utilities.

To put the cost of utilities in perspective, sort out the various components: electricity (for lights and appliances), heating, cooling, water, sewer, refuse disposal, and even the telephone bill. Don't forget cable TV, if you have it.

One way to set up a predictable utility budget, particularly for heating and cooling expenses, is to ask for a ''level payment,'' or budget, account, if the utility has one. A budget account allows a customer to pay the same amount each month, usually for 10 months, regardless of usage.

The disadvantage is that you may build up a significant balance in the account, thus giving the utility company the use of your money interest-free. On the other hand, if the cost of service runs beyond your monthly budget, you have a negative balance in the account and the utility is helping to finance your heating and cooling expense for part of the year.

Estimates for new homes are based on square footage, type of heating, quantity of insulation, windows, and the location of the house. * Insurance.

Because of inflation these days, many houses are underprotected against loss. If you do have a loss, you may be penalized. Insurance companies usually require coverage that is at least 80 percent of the replacement value of the house. Thus , it's a good idea to review your insurance policy once a year.

Homeowners should take note of such items as deductibles, special endorsements for valuable items, and built-in coverage for insulation so as to get the best coverage at the best rate.

Again, the annual cost can be split by 12 so as to determine the monthly expense. Annual premiums vary according to the type of coverage and the home.

To assist with budgeting, a bank or mortgage company will often add the cost of insurance and property taxes to the mortgage payment. Premium notices or tax bills are sent to the bank that pays them.

If that option is not available, a homeowner can open a special savings account where monthly payments are automatically made to the special account from the homeowner's checking account. Money in the special account draws interest until it's time to pay the bills.

Either system eliminates being caught with a big bill during a tight month. * Other expenses.

Decorating and landscaping can be major expenses and demand careful planning.

Draperies, appliances, furniture, accessories, and carpeting can cost thousands of dollars. Better Homes and Gardens magazine recommends focusing on essentials and planning to fill in the gaps as money becomes available.

You should take just as much care in deciding what to plant around the house and where it should go. Trees and shrubs do not come cheaply.

You can get more than aesthetic satisfaction from a well-designed landscape. Properly placed trees and shrubs can cut utility bills, for example. Too, that charming yard may eventually be the extra factor that helps to sell your house faster.

Remember, a house is not a home until there's somebody and something in it.