The Element of water symbolizes the flow of human feelings, and it is no wonder that the Moon, that great significator of emotion, finds its home in a water sign, Cancer. A horoscope heavily endowed with planets in the water signs shows an individual who trusts his/her feelings, an individual who is emotional rather than mental.
The extraverts in particular will accept the judgement of society without question, and all the "pure" water types, whether introverted or extraverted, tend to have opinions rather than ideas. If extraverted, these people are exemplars of all social graces, for they are attuned to the feelings of others. The introverts are the people we typically call "still waters that run deep", those brooding, sensitive, inarticulate souls who remain locked in an internal cocoon.
Because they live by their feelings, the water signs types (unless they also have a great many planets in air signs) will neglect thinking values all together.
The Sun represents the ego, and the ego's ability to transmit the intentions of the personality, coupled with its ability to filter outer stimuli, is perhaps unique. The Sun's powerful rays of light, when in strong aspect to others planets, enhance or magnify its intentions and purpose. But let's not suppose we have an overcast day outside. We say the sun isn't out, but that's not true. The sun is always out during the day light hours. On a cloudy day we still see where we are going without the use of artificial light, but we are not necessarily aware of the sun's presence. So it is with many who's Suns are placed in the element of water. There are veils and many layers of psychic and/or emotional material between those whose Sun occupies a water sign and the object of their attention or interaction. You won't get sunburned by these types, but you will get a sense that there is more going on underneath the surface than above.
Water puts out fire, so when the watery nature is strong those whose Suns are placed in water signs won't express themselves as powerfully on the outside as the fiery Sun people do. But their inner lives are a different story! Behind the clouds and fog are many kinds of experiences, both inspirational and turbulent. And it is by wrestling with these extremes that enlightenment comes for such individuals. When the Sun, a fire planet, is placed in water sign, the fire/water theme may be strongly apparent elsewhere in the chart. Both elements have to be honored. Because water signs absorb feeling and sensation, and because the Sun symbolizes how we express that which is part of our inner being, it is the water Sun's task to externalize those watery depths in whatever way it can.
In the birth chart when we see an abundance of the elements of water we immediately know that this certain individual has a great capacity to feel. If the planets that are placed in water signs are nicely aspected and free to "flow", they often indicate people who will use these gifts in a caring and sensitive way. They may become connected to the healing professions or helping professions, using their psychic and psychological awareness in a way that keeps the principle active for themselves and also circulates the knowledge to those with whom they are connected. They may be artists, or musicians, mystics or poets, teachers or group leaders who, by virtue of their ability to tap into their feelings, inspire others to do so. This process however is not always easy.
The last two hundred years have focused our attention on industrialization and high technology. We have gone to an extreme to incorporate technology and science into our lives, developing mega-minds and corporate wizards who live in a gray chrome and glass world. All dressed the same, acting the same by responding on command almost robots. These are scenes that flash before our children' eyes and penetrating their very open, psychic and impressionable young mind. Meanwhile they are told that the expression of feeling is not allowed. Girls get to express it a little longer(at least through their teenage years), but boys are told at a very young age not to cry. Because this shows weakness and isn't very manly. But soon girls, too, are mocked when the natural expression of tears overflows.
Many of the diseases of today can be linked to principles of limiting feeling or repressing the water principle in our lives. When we observe a dam built to contain or hold back the natural flow of water, we note that a tremendous amount of manmade force must be employed to halt the natural flow. Imagine what we do to our bodies by obstructing the free flow of he water process. It takes a lot of strength and resistance to keep the feelings--or natural flow of emotional responses--back. Our bodies have a natural way of releasing water or expressing feelings locked inside--tears. Yet many feel stupid or even guilty when they let the tears flow. Think of how healing it is for a good cry. It's similar to a refreshing shower, except it's being taken internally.
When the water function is blocked in a person's life it may show up in the chart as a lack of planets in water signs. In these cases, the person has often been blocked from expressing the natural flow of his/her feelings or made to feel the need to repress them for fear that if they were let out they would explode. The combination of water with fire, for instance, is quite volcanic. The hot fiery emotions mix with the water and steam in a cauldron several levels below consciousness, until a transit, eclipse, lunation, or progression sets them off and creates a highly volcanic eruption. This is often true with Scorpio, since it is the fixed water sign. The water stays contained beneath the surface, sustaining the feelings before they can proceed.
The mixture of water with air is very Pisces-like, creating clouds of rain which are sometimes turbulent, like thunder and lightening over the ocean, at other times soft and soothing, like a summer shower. When expressed properly, the water/air mixture can create verbalization or vocalization of feeling-writers, musicians, songwriters, poets, etc. One of the most productive mixtures of air and water in recent times were the Beatles. Which featured two creative intellects, (John&Paul) with their Sun signs in air (Libra&Gemini) supported by two musicians (George&Ringo) with their Sun signs in water(Pisces&Cancer).
Earth with water usually create a harmonious flow. Earth needs water to grow and survive. Water can use a contain such as earth to keep from spilling out and running rampant, potentially destroying everything in its path. When earth and water are too dominant in a birth chat without the addition of the other two elements, "mud" is created or a sense of stasis and complacency with the current situation; motivation is lacking.