The drain pipe at my house is clogged around 10 feet away from the house, outside (on the patio)my neighbor says that it must be that the septic tank is full?I have about 35years living here ,and I never heard that I had a septic tank .My father own this house since 1945.wich she says that she had to remove hers in 1965 when she moved in,and that it looks like the rest of the houses had them removed.how can I find out if my house has one (wich I doubt)I live in san diego ca, zip code 92113

As you are close to the centre of town and only have a small yard, it is unlikely that you have a septic and drain field. Drain fields take up a fair bit of space.
However, it is an old property.

Look at your water bill, do they charge you for sewer? If not, you probably have a septic. However, I can't imagine a septic tank lasting that long without being pumped. OR, call the water and sewer utility, give them the address and they should be able to tell you.