The Cholmondeley estate records are an excellent resource for finding medieval ancestors in Cheshire. Data for Towns in Cheshire is rare because in the medieval period Cheshire was exempt from national taxation, having its own taxation system, the Mize. The following description of the Mize was given in 1881:

The county of Chester, upon the accession of every new Earl of Chester, was in the habit of presenting the owner of that earldom with a subsidy of three thousand marks, which was raised in a mode peculiar to the county, by a rate called a mise or mize. By this mize, which was of very ancient date, every vill in the county was estimated at a certain small sum, which was supposed to represent its whole value in proportion to the whole value of the county.

A few examples may be given to show the sums which were originally imposed in Frodsham and some of the other places in Edisbury hundred. Thus in Frodsham the mize was £1. 16s. ; in Helsby, 10s. ; in Kingsley £1 ; in Manley, 10s. ; and in Norley, 10s.

An Account of the Ancient Town of Frodsham in Cheshire, by William Beamont

It can often be difficult to find sources prior to the introduction of Parish records, especially in the case of Cheshire, which had its own tax system. We therefore have to do without many medieval tax documents, which otherwise would have been an excellent source.

The estate records mention Whitters from the 14th to the 18th century, mostly in and around Frodsham. The earliest mentions that I have found so far are from the years 1317 and 1324.

Grant in fee by Henry, son of William le Masun dyer of Frodesham to Henry his son, of half burgage lying in the township of Frodesham on Rucrof, between the land of Henry Vytter and the land of William Pinke […]

1317, Cholmondeley Estate records

In the Grant from 1324 (by Enias the Welshman of Chester and Dionisia his wife to Richard Pingke de Frodesham) a Robert Witir is listed as a witness. There are many other references to Whitters as a witness in many other Grants from the 14th century, in different writing variants, such as Wetor, Wytor, Wyter, Wyttor and Vytor.
In the period from 1352 to 1364 alone there are four mentions of a Henry Wetor/Wytor and in the period from 1371 to 1398 there are six mentions of a Nicholas Wetor/Wytor, all in Frodsham.

Grant in fee by Henry Wetor to Henry le paniermaker, of ¼ part of a burgage in Frodesham in Ricroft between the half burgage of the said Henry and a ¼ part of the burgage of Edayn Burgeys […]

1362, Cholmondeley Estate records

Grant by Henry Wyter, Prior of the House of St Giles in Chester, and the convent thereof, to John de Holford of piece of land called Redbrokescroft in Toft which the House formerly had by the gift of Hugh de Toft. Given at Toft.

11 Apr 1369, Cholmondeley Estate records

Grant by Thomas Torfot de Frodesham to Randle de Hokenell, vicar of the church of Frodesham, of a burgage with appurtenances in Frodesham recently purchased of Henry le Piper de Preston, between the burgage of Nicholas Wetor and the ½ burgage of Richard Torfot del Nethurton the elder.

1389, Cholmondeley Estate records

For the 15th century I have only been able to find one secure mention in the estate records; Thomas Wyttor and Robert Wyttor are listed there as witnesses in the nuncupative will of Richard Williamson of Frodesham.

In the 16th century there are again many sources mentioning Whitters in Frodsham. Starting with the estate records, wills, grants and of course the already well-known Parish records.
So it seems that the family has lived in Frodsham since the Middle Ages.